Go karting project report Degree level

GO-KARTING
K.B.P. COLLEGE OF ENGG. SATARA.(ProductionEngg. Dept.) Page 1
CHAPTER 1
INTRODUCTION

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Figure 1: Go-kart
In the 1950’s a group of tinkerers and thrill seekers in Southern California welded
together a crude frame from steel tubing, mounted it on wheels intended for wheel barrows,
powered the contraption with a small 3 HP engine intended for lawn mowers and raced it around
the parking lot of the Rose Bowl in Pasadena. These vehicles, now called "go-karts" have grown
into a multi-billion dollar industry in the USA and throughout the developed world. They are
made, sold, and used exclusively as recreational racers. They are not designed for transportation
and it is illegal in most places to drive them on the road.
These vehicles are typically 30 inches wide, 4 to 5 feet long, and weigh between 50 and
70 pounds. They are simple and inexpensive to build and operate and they can travel on rough
terrain and roads at speeds exceeding 20 miles per hour. It is estimated that large volume export
OEM contracts could be negotiated somewhere near half this amount. Alternate Asian sources
particularly China or S. Korea might yield lower cost designs. Chinese-made 4-cycle irrigation

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pump engines are widely available in Asia for around $100 and these may be substituted for
lawn mower engines in Asian designs. An additional consideration in favor of the irrigation
pump engines is that 4- cycle engines are less polluting and many countries in Asia are phasing
out the use of 2-cycle engines for that reason.
Normally a 30-inch wheelbase is used with 1" by 36" threaded axles and 3 to 6 inches of
ground clearance depending on type of terrain the vehicle is expected to traverse. A very
elementary steering system of the tie-and-rod variety is sufficient. Brakes may be 4-1/2 inch
band or drum design. Eight-inch to 14-inch standard wheels from the garden supply industry
may be utilized. The other significant components are the clutch and sprocket assembly,
bearings, and a throttle control assembly.
Even in their most primitive forms go karts may be adapted as transportation technology
in developing countries to leverage economic growth and poverty alleviation. Go karts offer a
simple and inexpensive technology that meets many rural transportation needs. The technology
is a bridge between simple pushcarts and rickshaws on one hand and the automobile and truck
technology designed to western specifications on the other. The relative inefficiency of the
former technology is the very cause of poverty in many areas while the cost and technology
burden of the latter make them inaccessible to the poor.

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Feasibility of a Sustainable Go-Kart
The necessary conditions for sustainability of a go-kart project for rural development
include economic, social, and technical issues. Some of the questions that must be addressed
include the following: (Howe and Richards 1984, World Bank 1996, Howe 1999)
 Transport infrastructure: Can the existing rural road network be used by
go-karts?
 Demand for new services: Will the villagers use this technology? Do they
need it?
 Financial feasibility: Will capital be available for investment in go-kart
manufacturing?
 Financial feasibility: Can the villagers afford to purchase, operate, and
maintain go-karts? Will credit be available?
 Economic feasibility: Will the use of go-karts by villagers increase their
standard of living?
 Technical feasibility: Does the technical expertise exist among villagers to
operate and maintain these machines?
 Industrial feasibility: Does an industrial infrastructure exists that can
supply parts and labor for the manufacture of go-karts?
 Political feasibility: Will go karts and their environmental and economic
impact on rural life be acceptable to those in power?
 Social sustainability: Will the new technology be adopted as an integral
part of the rural society and will benefits of improved transport reach all
sections of the community? Will it help the poor?
A well-developed cottage industry infrastructure exists in Bangladesh even in rural areas
for the introduction of go-kart technology. Both machine shops and welding shops may be found
at most small population centers throughout the country and the operators are skilled in their
work. Small two-cycle engines have been adapted for urban and rural transport as "baby taxis"
and "tempos" throughout the country. These are 3-wheeled passenger as well as freight vehicles.
Their maintenance and chassis manufacture is a wide-scale cottage industry in both urban and
rural areas.

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Bicycles, rickshaws, and rickshaw-based freight vehicles called "vans" are also
manufactured in small shops throughout the country. Truck maintenance shops provide yet
another source of technical skill that may be adapted for the introduction of go-karts to the
country as a cottage industry in a de-centralized implementation. There are many motor sports in
the world. Bikes, Cars, Formula one are examples of them. The drivers in these are very
professional. They can drive it very fast. But there are also motor sports which do not need
professional drivers and need no great speed. The vehicles used are also very cheap. Such a
motor sport is Go-Karting
They resemble to the formula one cars but it is not as faster as F1 and also cost is very
less. The drivers in go-karting are also not professionals. Even children can also drive it. Go-
karts have 4 wheels and a small engine. They are widely used in racing in US and also they are
getting popular in India.

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Scope of the project
Go-Karting is a big craze to the Americans and Europeans. It is initially created in United
States in 1950s and used as a way to pass spare time. Gradually it became a big hobby and other
countries followed it. In India go-karting is getting ready to make waves. A racing track is ready
in Nagpur for go-karting and Chennai is also trying to make one.
Indian companies are also producing go-karts in small scale. MRF and Indus motors are
the major bodies in karts and they are offering karts between 1lakh and 3 lakh. But to make go-
karts popular, the price must come down. For that, many people are trying to build one under 1
lakh and we had also take up the challenge. A go-kart just under Rs. 25,000/-. So we are sure that
our project will have a high demand in the industry and also we are hoping to get orders from the
racing guns.
About go – karts
Go-kart is a simple four-wheeled, small engine, single seat racing car used mainly in
United States. They were initially created in the 1950s. Post-war period by airmen as a way to
pass spare time. Art generally accepted to be the father of karting. He built the first kart in
Southern California in 1956. From them, it is being popular all over America and also Europe.
A Go-kart, by definition, has no suspension and no differential. They are usually raced on scaled
down tracks, but are sometimes driven as entertainment or as a hobby by non-professionals.
Karting is commonly perceived as the stepping shone to the higher and more expensive ranks of
motor sports. Kart racing is generally accepted as the most economic form of motor sport
available. As a free-time activity, it can be performed by almost anybody and permitting licensed
racing for anyone from the age of 8 onwards.
Kart racing is usually used as a low-cost and relatively safe way to introduce drivers to
motor racing. Many people associate it with young drivers, but adults are also very active in
karting. Karting is considered as the first step in any serious racer’s career. It can prepare the
driver for highs-speed wheel-to-wheel racing by helping develop guide reflexes, precision car
control and decision-making skills. In addition, it brings an awareness of the various parameters
that can be altered to try to improve the competitiveness of the kart that also exist in other forms
of motor racing.

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Go-Karts in India
Go-karts emerged in India in 2003 from MRF, which has a 250cc two-stroke engine,
which produce 15 bhp of power, which costs around 3 lakh. Indus motors are also offering Go-
karts for 1 lakh to 3 lakh. There are racing tracks in Nagpur for go-karting, which is known as
the home of go-karts in India. Many people take part in the racing and its getting popular.
Go-Karts in Foreign Countries
Go-karts in foreign countries have much more performance than the Indians. One type is
a single engine 160cc 4-stroke kart with a maximum speed of around 40 mph and second type, a
twin-engine 320cc 4-stroke kart used in outdoor with a maximum speed of 70 mph. There are
hundreds of racing tracks in US for karting and also they are much more professional than the
Indians.

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Parts of a go – kart
In a Go-Kart, there are mainly six parts. They are,
1. Chassis
2. Engine
3. Steering
4. Transmission
5. Tyres
6. Brake
7. Electric Starter
CHASSIS:
The chassis is an extremely imported element of the kart, as it must provide, via flex, the
equivalent of suspension to give good grip at the front. Karts have no suspension, and are usually
no bigger than is needed to mount a seat for the driver and a small engine. Chassis construction
is normally of a square tube construction, typically MS with different grades. In this kart, we use
MS tube with 1” diameter. The chassis support the power unit, power train, the running system
etc.
The Chassis construction:
The chassis of a Go-Kart consists of following components suitably mounted:
i. Engine
ii. Transmission system, consisting of the chain sprocket, rear axle.
iii. Road wheels.
iv. Steering system.
v. Brake.
vi. Fuel tank.
All the components listed above are mounted on the conventional construction, in which
a separate frame is used and the frameless or unitary construction in which no separate frame is
employed.

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Conventional Construction: In this type of chassis construction the frame is the basic unit to
which various components are attached and body is bolted onto the frame later on.
Function of the frame:
1) To support the chassis components and body.
2) To withstand static and dynamic loads without undue deflection or distortion.
Loads on the frame:
1) Weight of the vehicle and the passenger, which causes vertical bending of the side members.
2) Vertical loads when the vehicle comes across a bump or hollow, which results in longitudinal
torsion due to one wheel lifted (or lowered) with other wheels at the usual road level.
3) Loads due to road chamber, side wind and cornering force while taking a turn, which results
in lateral bending of side members.
4) Load due to wheel impact with road obstacles may cause that particular wheel to remain
obstructed while the other wheel tends to move forward, distorting the frame to parallelogram
shape.
5) Engine torque and braking torque tending to bend the side members in the vertical plane.
6) Sudden impact loads during a collision, which may result in a general collapse.
Frame construction: A simplified design representing the frame shows the longitudinal
members ‘A’ and cross members ‘B’. The frame is narrowed at the front as shown in to have
better steering lock, which gives a smaller turning circle. ‘C’ is the brackets supporting the body.
The extension of the chassis frame ahead of the front axle is called Front overhung, whereas its
extension beyond the rear is called Rear overhung. The engine and the transmission are all
bolted together to form one rigid assembly which is mounted usually on the rear end of the
frame. Various cross-sections used for the side members or cross-members of the chassis frame.
We used Channel section. It is seen that the channel section have bending stiffness’s as 6.5 and
7.2 compared to a Solid square with equal cross-sectional area whose stiffness is taken as 1.

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Materials for frame: There are so many materials can be used for making frames like steel,
iron. We used MS for chassis.
Defects in frame: The only prominent defect that usually occurs in the frames due to accidents
is the alignment fault. This may be checked by means of a plumb line. The vehicle is placed on a
level surface and by suspending plumb line from four different points on each side of the frame;
their position on the ground is marked. The vehicle is then taken away and the diagonals are
measured between corresponding points. These should not differ by more than 7 or 8 mm. If any
of the corresponding diagonals do differ by more than this amount, the frame is out of alignment.
The possible cause, then, may be any one of the following:
1) The dumb irons or side members may be bent.
2) Cross members may be bulky.
3) Some rivets may be loose or broken.
If the damage to the frame members is small, they can be repaired by means of a hydraulic jack
and wringing irons. If the damage is more, the bent frame member may be heated to straighten it.
Another alternative may be to cut the damaged part and weld a new one instead.
Engine:
An engine of a go-kart is usually a small one about 80cc. In this kart, we use a kinetic
Honda Single Cylinder 98cc 2-stroke petrol engine, which produces about 7.7 BHP@5600 rpm..
We use 2- stroke engine because this is used for racing. So there is no need of mileage.
Steering system:
The steering of a go-kart is very sensitive. Rack-and-pinion steering is quickly becoming
the most common type of steering on cars, small trucks and SUVs. It is actually a pretty simple
mechanism. A rack-and-pinion gear set is enclosed in a metal tube, with each end of the rack
protruding from the tube. A rod, called a tie rod, connects to each end of the rack.
The pinion gear is attached to the steering shaft. When you turn the steering wheel, the
gear spins, moving the rack. The tie rod at each end of the rack connects to the steering arm on
the spindle

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Transmission
Transmission means the whole of the mechanism that transmits the power from the
engine crankshaft to the rear wheels. In this vehicle, the power from the engine is transmitted to
the sprockets using chain, i.e. this is chain drive. The driver sprocket has 9teeth and driven
sprocket has 45 teeth. Usually go-karts do not have a differential and so we eliminate differential
from our vehicle also. And also this go-kart has no clutch and gears because this is automatic
transmission. Belt and pulley type CVT issued in this kart. The power from the engine is
transmitted to the rear two wheels using chain drive. We use chain drive because it is capable of
taking shock loads.
Introduction: The word ‘transmission’ as introduced in the beginning of this book means the
whole of the mechanism that transmits the power from the engine crankshaft to the rear wheels.
Necessity of Transmission: The question as to how far is the transmission necessary in a vehicle
may be answered by considering.
 Variation of resistance to the vehicle motion at various speeds.
 Variation of attractive effort of the vehicle available at various speeds.
Chain Drive:
Determining the number of teeth for the driver sprocket Choose the suitable number of
teeth in Accor- dance with the recommendations regarding sprocket selection criteria.
Determination of chain speed on grounds of the sprocket revolution is based on the formula:
chain speed:
v = do.n/19,100 (m/s) wherein:
do = sprocket reference diameter in mm
n = sprocket revolution (r.p.m)
v = chain velocity (m/s) 19,100 = constant
The sprocket revolution can also be derived from chain speed and the reference diameter
by simply rearranging the above formula: Sprocket revolution: n = (r.p.m.)
finally, the required sprocket reference diameter can be derived from the shaft revolution and
chain velocity: do = (mm)

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Tyres
For go-karts, wheels and tyres are much smaller than those used on a normal car. The
tyres will have increased grip and a hard one. And also it can withstand the high temperature. In
this kart, we use tyres having 15” dia for front and for rear. This is used for an aerodynamic
shape. The tyres must have pressure of at least 18 psi.
Figure 2: Parts of tyre
Wheels and tyres
Introduction
The importance of wheels and tyres in automobile is obvious. Without the engine the car
may be towed, but even that is not possible without the wheels. The wheel, along the tyre has to
take the vehicle load, provide a cushioning effect and cope with the steering control. The various
requirement of an automobile wheel are:
1. It must be strong enough to perform the above function.
2. It should be balanced both statically as well as dynamically.
3. It should be lightest possible so that the un sprung the wheel easily.
4. It should be possible to remove or mount the wheel easily.

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5. Its material should not deteriorate with weathering and age. In case, the material
is susceptible to corrosion, it must be given suitable protective treatment.
Types of tyres
The use of solid tyre on automobile is now obsolete and only the pneumatic tyres are universally.
There pneumatic tyres may be classified according of following consideration:
1. Basic construction.
2. Use.
3. Ability to run flat.
Figure 3: Construction of tyre

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Tyre Specifications
1 .Tyre Width:
The75 is the width of the tyre in millimeters (mm), measured from sidewall to sidewall.
Since this measure is affected by the width of the rim, the measurement is for the tyre when it is
on its intended rim size.
2 .Aspect Ratio:
This number tells you the height of the tyre, from the bead to the top of the tread. This is
described as a percentage of the tyre width. In our example, the aspect ratio is 75, so the tyres
height is 75 percent of its width, or 56.25 mm (75 x 75 =56.25 mm, or 2.25 in). The smaller the
aspect ratio, the wider the tyre in relation to its height. Two tyres with different aspect ratios but
the same overall diameter high performance tyres usually have a lower aspect ratio than other
tyres. This is because tyres with a lower aspect ratio provide better lateral stability. When a car
goes around a turn lateral forces are generated and the tyre must resist these forces. Tyres with a
lower profile have shorter, stiffer sidewalls so they resist cornering forces better.
3 .Tyre Construction:
The R designates that the tyre was made using radial construction. This is the most
common type of tyre construction. Older tyres were made using diagonal bias (D) or bias belted
(B) construction. A separate note indicates how many plies make up the sidewall of the tyre and
the tread.
4 .Rim Diameter:
This number specifies, in inches, the wheel rim diameter the tyre is designed for. The
service description consists of two things.
Load Ratings
The load rating is a number that correlates to the maximum rated load for that tyre. A
higher number indicates that the tyre has a higher load capacity. The rating “105,” for example,
corresponds to a load capacity of 2039 pounds (924.87 kg). A separate note on the tyre indicates
the load rating at a given inflation pressure.

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Speed Rating
The letter that follows the load rating indicates the maximum speed allowable for this tyre (as
long as the weight is at or below the rated load). For instance, S indicates that the tyre can handle
speeds up to 112 mph (180.246 kph). See the chart on this page for all the ratings.
5 . Calculating the tyre Diameter:
Now that we know what these numbers mean, we can calculate the overall diameter of a tyre.
We multiply the tyre width by the aspect ratio to get the height of the tyre. Tyre height = 75 x 75
percent = 56.25 mm (2.25 in) Then we add twice the tyre height to the rim diameter. 2 x 2.25 in
+ 15 inches = 19.5 in (487.5 mm) this is the unloaded diameter; as soon as any weight is put on
the tyre, the diameter will decrease.
 Effect of air pressure on tyre performance:
1 .On dry road/ off-road:
Only properly inflated tyres produce quick response and good handling. The
underinflated tyre require more steering input to initiate maneuvers and are slower to respond.
Beside, under inflated tyre also feel out of synchronization during transition, i.e., instead of
moving in unison, the rear tyre reaction lags behind those of the front tyres, resulting in a
detached sensation being transmitted to the drivers.
2 .On wet road:
A significant underinflated tyre would allow the centre of the tread to collapse and
become very concave, trapping water rather than allowing it to flow through the tread design.
Thus driving the vehicle with the underinflated tyres would be more difficult and would force the
driver to show down to retain control.

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Tyre materials include basic ingredients like
1.Polymers: They are the backbone of rubber compounds. They consist of natural or synthetic
rubber.
2.Fillers: They reinforce rubber compounds. The most common filler is carbon black although
other materials, such as silica, are used to give the compound unique properties.
3.Softeners: Petroleum oils, pine tar, resins and waxes are all softeners that are used in
compounds principally as processing aids and to improve tack or stickiness of unvaulcanized
compounds.
4.Antidegradents: Waxes, antioxidants, andantiozonants are added to rubber compounds to help
protect tires against deterioration by ozone, oxygen and heat like merino, resole ML wax.
5.Curatives: During vulcanization or curing, the polymer chains become linked, transforming
the viscous compounds into strong, elastic materials.
6.Sulphur: along with accelerators and activators help achieve.
Tyre specification:
Tyre size
Front 3.5" x 10−4
PR (Ply Rating)
Rear 3.5" x 10−4
PR
Wheel And Tyre Trouble Shooting:
1. Wheel bounce or tramp: The most obvious reason for this is the eccentricity of wheel and
tyre. If on checking, eccentricity is not found, the defect may be due to incorrect tyre pressure,
statically unbalanced wheels or statically unbalanced brake drum. To determine which particular
wheels is causing bounce, inflate all tyres to higher pressure of 350 kpa and drive over the same
road. If now the bounce is eliminated, decrease the air pressure to recommended valve in one

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tyre at a time and repeat the road test. Repeat this procedure till the entire tyre has been tested in
manner, i.e., one tyre at the recommended pressure and three tyres at the higher pressure. When
the bounce again develops, the tyre at the recommended pressure is the defective one which must
be replaced. This method of isolating the defective tyres is very effective in case of cross ply
tyres, but is not so effective in case of radial tyres.
2. Wheel wobble or shimmy: This may be due to wearing out of the hub bearing of the wheel
affected in which case it should be replaced. This defect may also be caused due to dynamic
unbalance, which itself may be due to several reasons such as bucked wheel, incorrectly fitted
tyre, bent axle shaft.
3. Side wear of tyres: When the tyre wears more at the side than at the side than at the center, it
is due to low tyre pressure.
4. One-side wear of tyre: This may be due to incorrect camber angle of incorrect toe in or
sagging axle on account of overloading. Continues running on high cambered road may also
result in this type of were.
5. Centre: The reason for this is the high tyre pressure.
6 .Uneven tyre wear: This is due to bucked wheel or the tyre and wheel assembly being out of
balance. Sudden acceleration and braking also result in this type of were.
7. Uniform rapid wear: Driving on rough road or fast driving are the causes of the uniform but
rapid were. It is estimated that were of tyre at a speed of 80 kph. Is approximately twice than at a
speed of 50 kph.
8. Rapid were with feathered edge on the tread: This type of wear may be detected by placing
figure on the tread and moving slowly in the cross direction, first on one side and then on the
other. This means the tyre has also been skidding. This may be due to incorrect wheel alignment.
On rear axle this may be due to misalignment of chassis and displacement of axle.
9. Tread cracking:This is due to overloading, over inflation or under inflation.Typically,go-
karts will have a single rear drum brake, which is situated on the rear axle.The brake will capable
for stopping the kart running in 40 mph. The pedals actuated by the left leg operate the brakes.

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Brake
Principle: A drum brake is a brake that uses friction caused by a set of shoes or pads that press
against a rotating drum-shaped part called a brake drum. It goes without saying that brakes are
one of the most important control components of vehicle. They are required to stop the vehicle
within the smallest possible distance and this is done by converting the kinetic energy of the
vehicle into the heat energy which is dissipated into the atmosphere. The term drum brake
usually means a brake in which shoes press on the inner surface of the drum.
Figure 4: Drum Brake
Braking Requirements: The brake must be strong enough to stop the vehicle within a minimum
distance in an emergency. But this should also be consistent with safety. The driver must have
proper control over the vehicle during emergency braking and the vehicle must not skid .The
brakes must have good ant fade characteristics, their effectiveness should not decrease with
constant prolonged application. This requirement demands that the cooling of the brakes should
be very efficient.

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Stopping Distances for brake on basis of efficiency:
Table No: 1
Efficiency % Stopping Distance
30 km/h 50 km/h 80 km/h 100 km/h
100 3.2 9.8 25.2 25.2
80 4.4 12.2 31.5 31.5
60 6.0 16.3 42.0 42.0
30 12.0 32.6 84.0 84.0
The distances given in the table are approximate only and they vary with the type of the
road surface and condition of tyre tread. Thus the actual stopping distances will be more than the
values given in table which is based upon deceleration only. These depend upon:
1. Vehicle speed
2. Condition of the road surface
3. Condition of tyre tread
4. Coefficient of friction between the tyre tread and the road surface
5. Coefficient of friction between the brake drum and the brake lining
6. Braking force applied by the driver.
Construction: Drum brake components include the backing plate, brake drum, shoe, wheel
cylinder, and various springs and pins.
Backing plate: The backing plate provides a base for the other components. It attaches to the
axle sleeve and provides a non-rotating rigid mounting surface for the cam, brake shoes, and
assorted hardware.
Brake drum: The brake drum is generally made of a special type of cast iron that is heat-
conductive and wear-resistant. It rotates with the wheel and axle.

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Cam: It is situated between two brake shoes, which are operated by the brake pedal. It pushes
Brake shoe outward.
Brake shoe: Brake shoes are typically made of two pieces of sheet steel welded together. The
friction material is either riveted to the lining table or attached with adhesive. The crescent-
shaped piece is called the Web and contains holes and slots in different shapes for return springs,
hold-down hardware, parking brake linkage and self-adjusting components. The edge of the
lining table generally has three “V"-shaped notches or tabs on each side called nibs. The nibs rest
against the support pads of the backing plate to which the shoes are installed. Each brake
assembly has two shoes, a primary and secondary.
Brake lining: Linings must be resistant against heat and wear and have a high friction
coefficient unaffected by fluctuations in temperature and humidity. Materials that make up the
brake shoe include, friction modifiers (which can include graphite and cashew nut shells),
powdered metal such as lead, zinc, brass, aluminum and other metals that resist heat fade,
binders, curing agents and fillers such as rubber chips to reduce brake noise.
Normal braking: When the brakes are applied, cam get operated, which in turn pushes the brake shoes
into contact with the machined surface on the inside of the drum. This rubbing action reduces the rotation
of the brake drum, which is coupled to the wheel. Hence the speed of the vehicle is reduced. When the
pressure is released, return springs pull the shoes back to their rest position.
Automatic self-adjustment: As the brake linings wear, the shoes must travel a greater distance
to reach the drum. When the distance reaches a certain point, a self-adjusting mechanism
automatically reacts by adjusting the rest position of the shoes so that they are closer to the drum.
Here, the adjusting lever rocks enough to advance the adjuster gear by one tooth. The adjuster
has threads on it, like a bolt, so that it unscrews a little bit when it turns, lengthening to fill in the
gap. When the brake shoes wear a little more, the adjuster can advance again, so it always keeps
the shoes close to the drum.

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Figure 5:Internal Structure Of Drum Brake

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Electric start
Both Otto cycle and Diesel cycle internal-combustion engines require the pistons to be moving
before the ignition phase of the cycle. This means that the engine must be set in motion by an
external force before it can power itself. Originally, a hand crank was used to start engines, but it
was inconvenient and rather hard work to crank the engine up to speed. It was also highly
dangerous. Even though cranks had an overrun mechanism to prevent it, when the engine started,
a crank could begin to spin along with the crankshaft. The operator had to pull away
immediately, or else risk a broken wrist, or worse. Moreover, as engines evolved, they became
larger and compression ratios increased, making hand cranking an increasingly difficult matter.
The modern starter motor is a series-wound direct current electric motor with a solenoid switch
mounted on it. When low-current power from the starting battery is applied to the solenoid,
usually through a key operated switch, it pushes out a small pinion gear on the starter motor's
shaft and meshes it with the ring gear on the flywheel of the engine. The solenoid also closes
high current for the starter motor and it starts to run.
Once the engine starts, the key-operated switch is opened, a spring in the solenoid assembly pulls
the pinion gear away from the ring gear, and the starter motor stops. Modern starter motors have
a "bendy" — a gear and integral freewheel, or overrunning clutch, that enables the flywheel to
automatically disengage the pinion gear from the flywheel when the engine starts.
Starter motor assembly
Other than the main parts, the kart also contains some parts such as Mufflers. The muffler we use
is Baffle type. In baffle type, the exhaust gas passes through a series of baffles, which causes
maximum restriction and hence back pressure. The noise reduction takes place because the
length of travel of exhaust gases increases considerably. Other main part is the headlight. Head
light is provided at the front of the kart for sane night racing. The requirement of automobiles is
that these should illuminate the road ahead at a reasonable distance with sufficient intensity. Also
there is a plastic seat in the kart for the driver. The kart is single seated. There is also a bumper in
front of the kart.

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CHAPTER 2
DESIGN CALCULATION

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Specifications of a go – kart
Engine Displacement (cc) = 98
No. of cylinders = 1
Type of Fuel = Petrol
No. of Strokes = 2
Maximum power (bhp) = 7.7 bhp @ 5600 rpm
No. of gears / variator = Variator
Overall Length (mm) = 1600
Height (mm) = 700
Wheel Base (mm) = 900
Ground Clearance (mm) = 200
Kerb Weight (kg) = 4.43
Fuel tank capacity (litre) = 3.75
Brake = Drum
Type of Cooling = Air cooling

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Design and drawings
Chassis:
Type of Material =Square Tube
LxB= 40x40 mm
Axle:
Type of Material = M S
Length of Axle = 900 mm
Diameter of axle = 30 mm
Brake:
Position = Single Rear
Type = Drum Brake
Brake Diameter = 110 mm
Sprocket:
Type of Material = M S
Outer radius of sprocket =180 mm
No. of Teeth = 45
Fuel Tank:
Material = Sheet metal.(Galvanized steel)
Capacity = 3 .75 Liter
Steering Spindle:
Diameter of tube =25 mm
Material = Galvanized iron Tube.
Pedal:
Type of material = M S

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Diameter of Rod = 75 mm
Muffler:
Material = Aluminum
Greater diameter of muffler = 100 mm
Total Length = 450 mm
Smaller diameter of muffler = 50 mm

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Calculation of turning angle
Figure 6: Steering Gear Mechanism

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Calculation
COT𝜃=BP/IP
=3000/900
=3.33
1/tan𝜃=2.44
1/2.44=tan
𝜃=16.69°.
tan−1
0.40
COT∅=AP/IP
=3850/900
1/tan∅=4.27
∅=13.15°
Cot𝜃-Cot∅=c/b

GO-KARTING
Design
Design consists of application of scientific, principles, technical information and imagination for
development of new or improvised machine or mechanism to perform a specific with maximum
economy and efficiency.
Hence a careful design approach has to be adopted. The total design work has been split
up into two parts;
• System design
• Mechanical Design
System design mainly concerns the various physical constraints and ergonomics, space
requirements, arrangement of various components on main frame at system, man + machine
interaction, No. of controls, position of controls, working environment of machine, chances of
failure, safety, measures to be provided, servicing aids, ease of maintenance, scope of
Improvement, weight of machine from ground level, total weight of machine and a lot more. In
mechanical design the components are listed down and stored on the basis of their procurement,
design in two categories namely,
• Designed Parts
• Parts to be purchased
For designed parts detached design is done and distinctions thus obtained are compared to next
highest dimensions which are readily available in market. This amplifies the assembly as well as
postproduction servicing work. The various tolerances on the works are specified. The process
charts are prepared and passed on to the manufacturing stage.
The parts which are to be purchased directly are selected from various catalogues and specified
so that any body can purchase the same from the retails shop with given specifications.
System design
In system design we mainly concentrated on the following parameters:-
1. System Selection Based on Physical Constraints

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While selecting any machine it must be checked whether it is going to be used in a large – scale
industry or a small –scale industry. In our case it is to be used by a small scale industry .So space
is a major constrain. The system is to be very compact so that it can be adjusted to corner of a
room.
The mechanical design has direct norms with the system design. Hence the foremost job is to
control the physical parameters, so that the distinctions obtained after mechanical design can be
well fitted into that.
2. Arrangements of Various Components
Keeping into view the space restrictions the components should be laid such that their easy
Removal or servicing is possible. More over every component should be easily seen none should
be hidden. Every possible space is utilized in components arrangements.
3. Components of System
As already stated the system should be compact enough so that it can be accommodated at a
corner of a room. All the moving parts should be well closed and compact. A compact system
design gives a high weighted structure which is desired.
Man Machine Interaction
The friendliness of a machine with the operator that is an important criteria of design. It is the
application of anatomical and psychological principles to solve problems arising from Man –
Machine relationship. Following are some of the topics included in this section.
Lighting condition of machine.
4. Chances of Failure
The losses incurred by owner in case of any failure are important criteria of design. Factor safety
while doing mechanical design is kept high so that there are Less chances of failure. Moreover
periodic maintenance is required to keep unit healthy.
5. Servicing Facility
The layout of components should be such that easy servicing is possible. Especially those
components which require frequents servicing can be easily disassembled.

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Scope of Future Improvement
Arrangement should be provided to expand the scope of work in future.
Such as to convert the machine motor operated; the system can be easily configured to required
one. The die and punch can be changed if required for other shapes of notches etc.
6. Height of Machine from Ground
For ease and comfort of operator the height of machine should be properly decided so that he
may not get tried during operation. The machine should be slightly higher than the waist level,
also enough clearance should be provided from the ground for cleaning purpose.
7. Weight of Machine
The total weight depends upon the selection of material components as well as the dimension of
components. A higher weighted machine is difficult in Transportation and in case of major
breakdown; it is difficult to take it to workshop because of more weight.
Mechanical design
Mechanical design phase is very important from the view of designer as whole success of
the project depends on the correct design analysis of the problem.
Many preliminary alternatives are eliminated during this phase Designer should have
adequate knowledge above physical properties of material, loads stresses, deformation, and
failure. Theories and wear analysis. He should identify the external and internal force acting on
the machine parts.
This force may be classified
1] Dead weigh forces
2] Friction forces
3] Inertia forces
4] Centrifugal forces
5] Forces generated during power transmission etc.

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Designer should estimate these forces very accurately by using design equations. If he
does not have sufficient information to estimate them he should make certain practical
assumptions based on similar conditions. This will almost satisfy the functional needs.
Assumptions must always be on the safer side.
Selection of factors of safety to find working or design stress is another important step in
design of working dimensions of machine elements. The corrections in the theoretical stress
value are to be made according in the kinds of loads, shape of parts and service requirements.
Selection of material should be made according to the condition of loading shapes of products
environments conditions & desirable properties of material
Provision should be made to minimize nearly adopting proper lubrications methods.In,
mechanical design the components are listed down and stored on the basis of their procurement
in two categories.
1] Design parts
2] Parts to be purchased
For design parts a detailed design is done and designation thus obtain are compared to the next
highest dimension which is ready available in market.
This simplification the assembly as well as post production service work. The various
tolerances on the work are specified. The processes charts are prepared and passed on to the
work are specified.
The parts to be purchased directly are selected from various catalogues and specification
so that anybody can purchase the same from retail shop with the given specifications.

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Axle rotationalspeed calculations
(1). 5600RPM Motor x 9 Tooth Drive Clutch = (x) RPM x 45 Tooth Sprocket
(x) RPM = 1120 rpm
(2). 5600RPM Motor x Ratio (1) = (x) RPM x Ratio (5)
(x) RPM =1120 rpm
(3). 5600 RPM Motor x (4 x .375) = (x) RPM x (21.0164 x .375)
(x) RPM = 1066
9 Tooth Sprocket Pitch = 4
Tooth Sprocket Pitch = 21.0164
Chain Pitch = .375
15" Tire Diameter - Circumference = 47.125" or 3.9375' (Per Revolution of the
Tire)
1120RPM x 60 min./1 hour = 67,200 Rev/Hour
67,200 Rev/Hour x 3.9375 Feet/Rev = 264600 Feet/Hour
264600Feet/Hour x 1 Mile/5280 Feet = 50.11 Miles/Hour [MPH] (5600 Motor
RPM)
For the Standard/Recommended Motor RPM of 3600 the Speed = 29.6 RPM
Drive Selection Calculations:
Input Speed - 5600 RPM
Output Speed - 1120 RPM
H.P. - 7
Service Factor - S.F. -1.7 (Heavy Shock Load, Internal Combustion Engine)
Design Power - S.F. x H.P. = (1.7) x (7) = 12 H.P.
Ratio = 5

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N2(Driven) = N1 Driver x Ratio = 9 (Teeth) x 5 = 45 (Teeth)
n2= n1(N1/N2) = 5600 RPM (9 Teeth/45Teeth) =1120 RPM
D1= p/sin(180°/N1) = 0.375 in./sin(180°/9 Teeth) = 1.09in. (Driver)
D2= p/sin(180°/N2) = 0.375 in./sin(180°/45 Teeth) = 5.37 in. (Driven)
Center Distance - "C" - 40 Pitches (Usually between 30 and 50)
40 x 0.375 in. = 15 in. (Theoretical)
(Actual Center Distance is 16"), so 16" = (x) Pitches x0.375 = 42.7 Pitches
Chain Length - L = 2C + N2+N1/2 +(𝑁2 − 𝑁1)2
/4𝑃2
C
Chain Length - L = 2(42.7) + 45+9/2 + (45-9)/4𝑃2
(42.7)
Chain Length = 135.130 Pitches
Integral Number of Pitches for the Chain Length and Compute the Actual Theoretical
Center Distance
C = 1/4 [ (L-(N2+N1/2)) +( (𝐿 − 𝑁2 + 𝑁1/2)2
- (8(𝑁2 − 𝑁1)2
/4𝑃2
)1/2
)
C = 1/4 [ (135 -(45+9/2)) + ((135 − 45 + 9/2)2
-8(45 − 9)2
/4𝑃2
)1/2
C = 42.6 Pitches = 42.6 pitches x (.375 in.) = 16 in.
Angle of Wrap
Small
= 180° - 2sin−1
( 𝐷2 − 𝐷1/2𝐶 )
= 180° - 2sin−1
( 5.37 − 1.09/32)
= 164°
Large
= 180° + sin−1(
𝐷2 − 𝐷1/2𝐶)
= 180° + 2sin−1
(5.37 − 1.09/32)
= 195.3°

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Summary
Pitch of No. 35 Chain = 0.375 inch
Length = 135 Pitches = 135(0.375 inch) =50.62 inches
Center Distance = C = 16.0 in. (Maximum)
Sprockets = Single Strand, N0. 35, 0.375 in. Pitch
Small: 9 Teeth, D = 1.09 in.
Large: 45 Teeth, D = 5.37 in.

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Bearing calculation
Data: Rear Axle RPM =1120 RPM @ 5600 RPM Motor Speed
Go-Kart Speed is 50.11 MPH @ 5600 RPM Motor Speed
Rear Tires are 15” O.D. Diameter
13” Tires – Circumference = 40.841” = 3.403’ / Revolution
3.403 Feet/Revolution x 1 Mile/5280 Feet = .000645 Mile/Revolution
50.11 Miles/Hour x 1Rev/.000645 Mile = 77689.92 Rev/Hour
77689.92 Rev/Hour x 1 Hour/60 Minute = 1290 RPM
Front Axle RPM =1290 RPM @ 5600 RPM Motor Speed
Rear Bearings – 1120 RPM – Inner Race Rotating and Outer Race is Stationary
Front Bearings – 1290 RPM – Outer Race Rotating and Inner Race is Stationary
Radial Loads Front - 560 lbs.
Back - 690 lbs. Worst Case Scenario
An assumption was made for the axial loads. These loads only occur during the time the is
turning or skidding on its terrain. The highest axial loads on the bearings would occur at the
point where the Go-Kart is going at a high speed, turning while all wheels are on the ground, and
is at it’s fastest point before it overcomes the friction between the tires and its terrain. According
to the Machinery’s Handbook, the rubber can have a coefficient of friction as high as 4.0
depending what material it is riding/working on. For the go kart the following calculations were
made:
Coefficient of Friction = 2.0
Normal Force at Right Rear Tire = 153 lbs
Maximum Force on Tire Before Skidding = 306 lbs
For everyday use, normal driving and turning conditions, and various terrains, a friction factor of
2.was used and an axial load of 200 lbs. will be used for the bearing selections.

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Calculations
Rear Bearing Calculations
Radial Loads - 690 lbs. Bearing Calcs, Tables, and Bearing Selections were all
Axial Loads - 200 lbs. completed from our School Book.
Speed - 1120 RPM
Design Life of 2000 Hours (2 years)
Shaft Diameter - 30 mm
V = 1.0 (Inner Race Rotates) P = VXR +YT
X = .56
P = (1.0)(.56)(690 lbs.) + (1.5)(200 lbs.)
R = 690 lbs.
P = 684.4 lbs.
Y = 1.5 Assumption
T = 200 lbs.
fn= .355
fl= 1.58
C = Pfl/fn
C = (686.4)(1.58)/(.355) C = 3055 lbs.
(6206) Bearing [30 mm Shaft]
(6206) Bearing Co= 2320 lbs.
T/Co= 200 lbs./2320 lbs. = .086
e = .281
T/R = 200 lbs ./690 lbs. = .290
T/R > e

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Y = 1.54
P = (1.0)(.56)(690 lbs.) + (1.54)(200 lbs.) = 694.4 lbs.
C = (694.4)(1.58)/(.355) = 3090.6 lbs.
Bearing # 6206 "C" = 3350 lbs., which is > than calculated "C". [This Bearing is acceptable)
Figure 7: Bearing Mounting

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Front Bearing Calculations
Radial Loads - 560 lbs.
Bearing Calculations, Tables, and Bearing Selections
(280 lbs. per Bearing)
Axial Loads - 200 lbs.
were all completed from our School Book.
(100 lbs. per Bearing)
Speed - 1290 RPM
Design Life of 2000 Hours (2 years)
Shaft Diameter - 17 mm
The Front Wheels will use (2) Ball Bearings per Wheel.
V = 1.2 (Outer Race Rotates) P = VXR +YT
X = .56 (Table 14-5) P = (1.2)(.56)(280 lbs.) + (1.5)(100 lbs.)
R = 280 lbs.
P = 338.16 lbs.
Y = 1.5 Assumption
T = 100 lbs.
fn= .34
fl= 1.58
c=pfl/fn
C = (338.16)(1.58)/(.34) C = 1571 lbs.
(6203) Bearing [17 mm Shaft]
(6203) Bearing Co= 1010 lbs.
T/Co= 100 lbs./1010 lbs. = .099

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e = .30
T/R = 100 lbs./280 lbs. = .36
T/R > e
Y = 1.45
P = (1.2)(.56)(280 lbs.) + (1.45)(100 lbs.) = 333.2 lbs.
C = (333.2)(1.58)/(.34) = 1548.2 lbs.
Bearing # 6203 "C" = 1660 lbs., which is > than calculated "C". [This Bearing is acceptable]

GO-KARTING
Steering system design
Steering system requirements
A steering system must offer sufficient precision for the driver to actually sense what is
happening at the front tyres contact patch as well as enough “feel” to sense the approach to
cornering limit of the front tyres. It must be structurally stiff to avoid components deflections.
The steering must be fast enough so that the vehicle’s response to steering and to steering
correction to happen almost instantaneous and it must also have some self returning action.
The feel, feedback and self returning action are function of the kingpin inclination, scrub radius,
castor angle and self aligning torque characteristics of the front tyre.
Design of the steering system geometry
Although modern cars do not use 100% Ackerman since it ignores important dynamic
and compliant effects, the principle is sound for low speed man oeuvres. The competition track
set up allows only for low cornering speed. In this case the tyres are at small slip angles
therefore, 100% Ackerman is the best option.
In consultation with the team, in our primary phase of the design we decided the wheelbase and
the track width. However, at the beginning of the second semester a major decision was made to
use for this year competition the previous year chassis. Since the geometry used last year proved
to work well, the decision was made to use for this year project same 100% Ackermann
geometry.
Ackermann condition
For the Ackermann analysis the Ackermann condition is used to determine the
relationship between inner and outer wheel in a turn and the radius of turn.
General equation:
1
tan 𝜃𝑜
-
1
tan 𝜃𝑖
=
𝐿
𝐵
Where:
θo= turn angle of the wheel on the outside of the turn
θi= turn angle of the wheel on the inside of the turn
B= track width
L= wheel base
b= distance from rear axle to centre of mass

GO-KARTING
Figure 8: Steering mechanism
From the general equation we can calculate the turn angle of the wheel on the
Outside of the turn for a given inside wheel angle as follows:
B=900 mm
L=1550 mm
Θi=30°
1
tan 𝜃𝑂
=
1
tan 𝜃𝑖
+
𝐿
𝐵
=16.32°
Selection of the steering parameters
The initial decision of zero degree kingpin inclination had to be reconsidered since the 56
mm of scrub radius resulted is large and will give an excessive feedback to the driver. Therefore
4 degree kingpin inclination is to be build in the front upright design that will result in an amount
of scrub radius of 30mmcalculated for last year wheel offset. Since this amount is still grater than
10%of the thread width (Heisler 1989), new wheels with less offset have been found therefore
the resulting scrub radius is about 20 mm that is the amount we aimed for. The amount of castor
angle was set to 3.5 degree and is also build in the front Uprights. However, castor angle can be
adjusted by adjustment of the upper wishbone. This requires that one arm of the wishbone to be

GO-KARTING
shortened while lengthening the other arm by screwing in or out the adjustable spherical rodents.
Another possible adjustment is to assemble the upright in an inclined position on the hub axle but
this is not a handy method of adjustment.
Selection of the steering mechanism
From all manual steering systems the more suitable is rack and pinion steering for the
following reasons:
-has a simple construction;
- is cheap and readily available;
- has a high mechanical efficiency;
- has a reduced space requirement.
Since last year rack and pinion steering mechanism had an undesirable amount of free
play the decision was made to modify one of the two steering mechanisms sourced by the team
members as donations for the project. The rack and pinion steering box selected is from a Honda
Civic 1983 and has a5 teeth pinion gear and a pitch on the rack of 4.5mm.The steering box
assembly have been modified by Bruce Llewellyn, one of the team members. The rack has been
shortened and the assembly was kept in the original steering box. The input shaft is not in a
central position therefore the steering column will be connected to the input shaft through a
universal joint.

GO-KARTING
Steering movement ratio
The rack and pinion mechanism is designed to transfer the circular input motion of the
pinion into linear output movement of the rack. It was measured that for a full travel of the rack
of 295 mm the pinion has to be rotated 3.5turns
Xo=
295
3.5
=84.28
Therefore for one turn, the rack travel will be:
Considering the pinion to make one revolution then the input steering movement is
Xi=2𝜋R
Where, R = 190 mm is the radius of the steering wheel.
And the output rack movement is:
Xo=2𝜋𝑟
𝑟 =
84.28
2𝜋
=13.42
Then, the movement ratio can be calculated as input movement over output:
MR=
𝑋𝑖
𝑋𝑜
=
2𝜋𝑅
2𝜋𝑟
=
190
14
=13.57
Therefore the movement ratio is 14:1
We needed to know the movement ratio in order to determine the output load transmitted to the
tie rods for a given input load. For an effort of 20 N applied by each hand on the steering wheel
and considering no friction, the output load will be:
Fo= F1 xMR=560
Therefore the load transmitted to the tie rods is 560

GO-KARTING
CHAPTER 3
SYSTEMS USED
IN AGO – KART

GO-KARTING
Systems used in a go – kart:
Like every automobile, go-karts also have various systems. Mainly
There are 4 systems in this kart.
1. Fuel system
2. Ignition system
3. Lubrication system
4. Cooling system
1. Fuel system
The purpose of fuel system in SI engines is to store and supply fuel and then to pump to
carburetors. The fuel supply system also prepares the air-fuel mixture for combustion in the
cylinder and carries the exhaust gas to the rear of the vehicle. The basic fuel supply system
used in the vehicle consists of the following.
a) Fuel tank
b) Fuel strainer or Fuel filter
c) Air cleaner
d) Carburetor
The type of combustion that takes place in an engine is commonly called Burning.
Burning is an example of chemical change. In a chemical change as substance losses those
characteristic by which we recognize it and is changed to a new substances with different
properties. The petrol is burned in the engine and the products that result no longer resemble
petrol.
The petrol in the fuel lines differs from the petrol that is drawn into the engine. As it
passes through the carburetor and intake manifold and is mixed with aim some of the petrol is
changed from liquid to vapour. This process of vaporization is called a physical changed. No
new substance is formed since the petrol vapour is still recognized as petrol.

GO-KARTING
Diesel fuel oil and petrol are both mixtures of volatile hydrocarbons compounds of
hydrogen and carbon. A compound is a substance that can be separated by chemical means into
two or more simpler substances. Hydrogen and carbon are examples of elements. In chemistry an
element is defined as a substance, which cannot be separated into simpler substances by
chemical action.
Fuel Tank: It is reservoir of fuel oil for an engine. It is kept in and elevated position so that the
fuel will flow to the carburetor through the filter by gravity. Our fuel tank has a capacity of
5litre.
Fuel Filter: Dust, particles of dirt or other unwanted particles might be present in the petrol. This
petrol should be free from these particles. Therefore, the petrol filter is used.
Air Cleaner: Since the atmospheric air is highly cornices and contains dust and dirt particles, it
is allowed to enter the engine intake manifold only through an air cleaner.
Carburetor: The mixture of petrol and air burns in the combustion chamber of the engine. The
carburetor is a device to mix the petrol with air in the proper ratio for the purpose of combustion.
The quantity of petrol and air can be indifferent ratios. The quantity of petrol can sometimes be
more and sometimes less. The speed of the engine changes according to the richness of the petrol
in the mixture.
Function of a carburetor is
a) Meter the quantity of charge to give correct air-fuel mixture.
b) Atomize petrol into fine particles so that it burns quickly.
2. Ignition system
The ignition system used for small two-stroke engine is flywheel magneto type. The
advantage of this system is that it is set combined. The flywheel magneto is basically used only
for a single cylinder engine though ones suitable for multi-cylinder engine have also been
developed. The principles of this type of ignition can be easily understood with following
description.

GO-KARTING
Magneto Generator
The ignition magnet of a magneto generator, which produces alternating electrical
impulses in a low-tension armature winding or coil. At an appropriate moment the circuit
through the winding is broken by means of an interrupter, which forms an integrate part of the
magneto. A condenser connected across the breaker assures rapid cessation of the primary
current, and this results in the induction of a high tension impulse in a fine wire secondary
winding, which either surrounds the primary winding or is surrounded by it, both being wound
on a magnetic coil. Advantage of the magneto is its self-contained character. All the demands of
the system are in on compact unit from which it is necessary only to run a low-tension cable to
the lighting system and high-tension cable to the spark plug.
Fly wheel magneto (rotating magnet type)
1. Ignition Coil
2. Spark Plug
3. Ignition Switch
4. Flywheel Magnet
A small magnet is provided with laminated pole pieces and the assemblies cast in the
engine flywheel, which also acts as a cooling fan. In addition to the magnet, the magneto consists
of a coil with a w-shaped or three pole laminated core, an interrupter and a condenser, all of
these parts being mounted on a base plate or starter plate. The two curved slots in the stator plate
permit of adjusting the spark timing. As the poles of the core pass those of the magnet, the
magnetic flux passes through the coil first in one and then in the opposite direction and
alternating electric impulses is induced in it. When the flux has been well established the primary
circuit is closed and a moment later when the primary current is at its maximum, the circuit is
broken by the interrupter, which is actuated by a cam on the crankshaft. Magnetos also have a
device coupled to it so that the timing is advanced as the engine speed increases. This helps in
ignition of the charge in the cylinder. The magnetos are either fitted with build-in type of two
coils – one ignition coil and the other lighting coil or alternately they have separate ignition coil.
These are attached to a starter or fixed plate and terminate in soft-iron pole-pieces closely
matching the shape of the flywheel which rotates around them.

GO-KARTING
Ignition Coil
The coil consists, in fact, of two coils which may be considered as separated electrically,
although they are both wound on the same iron core and share a common terminal. One coil,
known as the primary, is fed from the battery, and the principle of operation depends upon the
fact that, if the supply to this coil is suddenly interrupted, then the voltage is created or induced
in the other coil known as the secondary. The voltage in the two coils can be considered for our
purpose to be in the same ratio as the number of turns of wire on the two coils, so that by
providing relatively few turns on the primary winding, and a very large number on the secondary
the necessary, high voltage is obtained. The voltage required to cause a spark between the
sparking plug points depends upon both the pressure of the mixture with the cylinder and the gap
between the points under average conditions a voltage of the order of 10,000 volts is needed.
Earlier it has been stated that the development of the higher voltage in the secondary winding of
the ignition coil only occurs when the electricity supplied to the primary winding is suddenly
interrupted. This interruption is arranged to take place at the correct time by the contact breaker
points.
Figure 9: Ignition Coil

GO-KARTING
Spark Plug
An essential part of the ignition system is the provision of electrodes within the engine
cylinder, across which the ignition spark can discharge. It is desirable to arrange that these
electrodes shall be easily accessible and they are, therefore, mounted on a screwed-in plug. A
sparking plug consist essentially of a steel body which bears the earthed electrode, an insulator,
and a central rode which forms the other electrode, fed from the distributor. The lower part of the
body is threaded to suit a screwed bole provided in the engine, the length of the threaded portion
known as the reach and varying with the plug design. The body of the plug seats on to a soft steel
washer when it is screwed into the engine. The insulator operates under particularly arduous
condition since not only must it withstand the high ignition voltage, but it’s lower and is
subjected to the full bear of combustion and it is also liable to mechanical shock. At one time, the
insulator was mode from porcelain but modern plugs use ceramics based on sintered aluminum-
oxide.
The central electrode is seated into the insulator and is provided with a screwed terminal
at the upper exposed end, often shaped on connector. The tip of the electrode, at which the spark
occurs, usually has an insert of heat-resisting metal such as nickel. The ignition voltage is about
25,000 volts and the distance between the central and earthed electrodes is about. 202 inch and is
adjusted by bending the outer electrode.

GO-KARTING
Figure10: Spark plug
3. Lubrication system
It is a common known that if two rough surfaces are rubbed together, there is a resistance
to the motion and heat is generated. In an IC engine surface which rubs together are not tough by
normal standards, yet if they are allowed to run in direct contact get one another, the temperature
more rise to so high a degree that local melting will occur and the surfaces will slide to seize. It
has been shown than even if the surfaces are super finished, seizing will occur unless lubrication
is provided.
The primary objective of lubrication is to reduce the friction and wear between bearing
surface. Lubrication accomplishes this requirement by interposing a film of oil between the
sliding surfaces. Other function of lubricating oil in internal combustion engines are, such as the
pistons by packing up heat and dissipating it through the crank case and reducing compression
losses by acting as a seal between the cylinder walls and piston rings.

GO-KARTING
A lubricant must be able to perform certain task in order to accomplish its purpose
satisfactorily. It must possess sufficient viscosity and oiliness to protect mechanical devices of
the necessary speeds, pressures and temperatures.
Types of Lubricants:
Lubricants are classified in three forms - fluid, semisolid and solid. Fluid oils are used in
automobile engine lubrication systems, semi solid oils are used in chassis lubrication. Solid
lubrication is done by using graphite and mica. Graphite often with oil to lubricate automobile
springs. The use of these types depends upon the work required and the surface to be lubricated.
Splash Lubrication System:
The lubrication system used in the engine is splash lubrication system. In this system, oil
is splashed over different working parts of an engine. Oil is contained in a through or sump. The
big end of connecting rod is provided with a ‘spoon or dipper’ or ‘scoop’. When the piston is at
the bottom of its stroke, the big end of connecting rod and crankpin dip into oil. The dipper picks
up oil and as the crankshaft rotates, oil is splashed up due to centrifugal force.
The splashed oil is in the form of a dense mist sprayed into fine particles over surfaces in
contact. Small cups are provided close to the bearing of the crankshaft. There are small holes in
these cups. The splashed oils fill up these cups from where it is supplied to the bearing.
Oil that is splashed onto cylinder walls speeds well when piston reciprocates while the piston
rings scarp the oil and get themselves lubricated. Drops of splashed oil drip from the inner side
of the piston and lubricate the gudgeon pin and bearings. The crankshaft bearings, valve
mechanism and timing gears are also lubricated by splashed oil.

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Figure 11: Lubrication system
4. Cooling system:
A lot of energy is produced due to the combustion of fuel inside the engine cylinder.
Only 30% of heat energy is converted into mechanical work. Out of the remaining heat (about
70%) about 40% is carried away be exhaust gases into the atmosphere. The remaining part of
heat energy(about 30%) is absorbed by engine cylinder, cylinder head, piston and engine valves.
It causes thermal stress in the engine parts, reduces strength of the piston, decomposition of
lubrication oil, burning of valves and it also reduces the volumetric efficiency of the engine.
In order to avoid the harmful effects of overheating, it is essential to provide some cooling
system for IC Engines. Generally, there are two main types of cooling system. Water cooling and
air-cooling. In two stroke petrol engine, air-cooling system is employed.
Air cooling:
For this cylinder is cast with a number of fins around the cylinder. This type of cylinder is
used by motorcycles and scooters and also in go karts .The air from the atmosphere dashes
against these fins and remove the heat from the cylinder.

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Technical specifications of kinetic honda dx/zx 100 cc
Table No: 2
Engine : Two-stroke/petrol
Transmission : Automatic
Engine Displacement : 98cc
Tachometer : No
Max Power : 7.7bhp@5600rpm
Max Torque : 1.0kgm@5000rpm
Wheel base : 1,215mm
Ground Clearance : N/A
Ignition : Electronic
Dry Weight : 99kg
Battery : 12V
Transmission Constant mesh, 5 speed gear .Gear shift Pattern 1-down,4-
upStarting system Kick/self.

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Working of two strokepetrol engine
The engine we used in this kart is a 2-stroke petrol engine. The 2- stroke engine has no valves.
Ports serve the purpose of admitting and exhausting the charge. These parts open into the
cylinder; they are covered and opened by the sliding piston.
Figure 12: Two-Stroke Engine Components
1st Stroke: Suction and Compression: The piston compresses the fuel-air mixture in the
combustion chamber as it travels towards the TPC position.

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Figure 13: 1 st Stroke
In this process, the piston uncovers the inlet port. Fresh charge of fuel-air mixture enters the
crankcase owing to vacuum produced in it. This is due to the upward movement of the piston.
Thus, in one stroke of the piston, two operations, via suction and compression are carried out.
The crankshaft on the follow-through moves through one half of a revolution.

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Figure14:2 nd Stroke
2nd Stroke: Expansion and Exhaust:
As the piston reaches the TDC position, a spark ignites the fuel air mixture. There is
enormous pressure due to the combustion of fuel. This pressure pushes the piston downwards
executing the expansion or power stroke .In doing so, the piston uncovers the exhaust port and
allows the spent gases to go out of the cylinder to the atmosphere. The pre-compressed fuel-air
mixture travels from the crankcase to the combustion chamber through the transfer port. The
fresh fuel air mixture is fed into the combustion chamber with the help of a deflector on the
piston head. It guides the mixture through the transfer port into the combustion chamber towards
its top. The deflector also allows expulsion of exhaust gases by the fresh fuel-air mixture. This
process is known as scavenging.
We conclude that during the second stroke, two operations, viz .expansion and exhaust
are completed. The crankshaft moves through the other half of a revolution. Thus the four cycles

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of operation, viz., admission, compression, expansion and exhaust are completed in one
revolution of the crankshaft. The four-stroke engine completes this cycle of operations in two
revolutions of crankshaft. It is expected from this argument that a two-stroke engine must
produce nearly double the power of a four-stroke engine of the same dimensions. The difficulties
encountered by the two stroke engines, i.e. mixing of fresh charge with exhaust gases, loss of
some fresh charge to the atmosphere and incomplete scavenging, reduces to a great extent, the
brake horse power of the engine.

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Types of braking systems
Records show that in 1901, a British inventor named Frederick William Lanchester
patented the first type of brake, known as the disc brake.
Since this time, there have been many braking system types created for our safety. The
brake was created to make our vehicle stop in time to avoid accidents by inhibiting the motion of
the vehicle. In most automobiles there are three basic types of brakes including; service brakes,
emergency brakes, and parking brakes. These brakes are all intended to keep everyone inside the
vehicle and traveling on our roadways safe.
If you or a member of your family has been injured in a car accident, the victim may be
entitled to receive compensation for their losses and damages including; loss of wages, medical
expenses, pain and suffering, and property damage.
Common Braking System Type
The most common types of brakes found in automobiles today are typically described as
hydraulic, frictional, pumping, electromagnetic, and servo. Of course, there are several additional
components that are involved with make braking smooth and more effective depending on road
conditions and different circumstances.
Some common types of braking systems include:
 Electromagnetic Brakes
Electromagnetic brakes use an electric motor that is included in the automobile which
help the vehicle come to a stop. These types of brakes are in most hybrid vehicles and use an
electric motor to charge the batteries and regenerative brakes. On occasion, some busses will use
a secondary retarder brake which uses an internal short circuit and a generator.
 Frictional Brakes
Frictional brakes are a type of service brake found in many automobiles. They are
typically found in two forms; pads and shoes. As the name implies, these brakes use friction to
stop the automobile from moving. They typically include a rotating device with a stationary pad

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and a rotating weather surface. On most band brakes the shoe will constrict and rub against the
outside of the rotating drum, alternatively on a drum brake, a rotating drum with shoes will
expand and rub against the inside of the drum.
 Pumping Brakes
Pumping brakes are used when a pump is included in part of the vehicle. These types of
brakes use an internal combustion piston motor to shut off the fuel supply, in turn causing
internal pumping losses to the engine, which causes braking.
 Hydraulic Brakes
Hydraulic brakes are composed of a master cylinder that is fed by a reservoir of hydraulic
braking fluid. This is connected by an assortment of metal pipes and rubber fittings which are
attached to the cylinders of the wheels. The wheels contain two opposite pistons which are
located on the band or drum brakes which pressure to push the pistons apart forcing the brake
pads into the cylinders, thus causing the wheel to stop moving.
 Servo Brakes
Servo brakes are found on most cars and are intended to augment the amount of pressure
the driver applies to the brake pedal. These brakes use a vacuum in the inlet manifold to
generate extra pressure needed to create braking. Additionally, these braking systems are only
effective while the engine is still running.
In some vehicles we may find that there are more than one of these braking systems
included. These systems can be used in unison to create a more reliable and stronger braking
system. Unfortunately, on occasion, these braking systems may fail resulting in automobile
accidents and injuries.
Parking and Emergency Braking Systems
Parking and emergency braking systems use levers and cables where a person must use
mechanical force or a button in newer vehicles, to stop the vehicle in the case of emergency or
parking on a hill. These braking systems both bypass normal braking systems in the event that
the regular braking system malfunctions.

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These systems begin when the brake is applied, which pulls a cable that passes to the
intermediate lever which causes that force to increase and pass to the equalizer. This equalizer
splits into two cables, dividing the force and sending it to both rear wheels to slow and stop the
automobile.
In many automobiles, these braking systems will bypass other braking systems by
running directly to the brake shoes. This is beneficial in the case that your typical braking system
fails.

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Transmission
Karts do not have a differential lack of a differential means that one rear tire must slide
while cornering; this is achieved by designing the chassis so that the inside rear tire lifts up
slightly when the kart turns the corner. This allows the tire to lose some of its grip and slide or
lift off the ground completely.
Power is transmitted from the engine to the rear axle by way of a chain. Both engine and
axle sprockets are removable, their ratio has to be adapted according to track configuration in
order to get the most of the engine.
In the early days, karts were direct drive only, but the inconvenience of that setup soon
led to the centrifugal clutch for the club level classes. Dry centrifugal clutches are now used in
many categories (Rotax Max is one example) and have become the norm as the top international
classes have switched to 125 cc clutched engines as of January 2007.
Transmission system
The mechanical power produced by prime mover is used to drive various machines in the
workshop and factories. A transmission system is the mechanism, which deals with transmission
of the power. And motion from prime mover to shaft or from one shaft to the other. The machine
tool drive is an aggregate of mechanism that transmits motion from an external source. To the
operative elements of the machine tool. Provide an appropriate working or auxiliary motion.
When The required motion is rotary ; the transmission takes place through mechanisms that
transfer Rotary motion from one shaft to another. Transmission of the motion from the external
source to the operative element can take place through Mechanical elements such as belts, gears,
chains etc.
Mechanical Transmission and its elements:-
1) Belt Transmission
2) Gear transmission
3) Chain Transmission

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Belt Transmission
Belt drive is one of the most common effective devices of transmitting motion and power
from one shaft to the other by means of a thin inextensible belt running over two pulleys. This
largely used for general purpose in mills and factories especially when the distance between the
Shafts is not very great. When the center distance between the two shafts is large than the tight
side of the belt should be the Lower one the pulley called drive is mounted on the driving shaft
while the other, which is mounted. On the shaft to which power is to be transmitted is called the
driven pulley or follower. When the Belt moves over the Pulleys there is always the possibility
of slipping between the belt and pulley. And hens the character of the motion transmitted is not
positive when positive action is required. Gears and chains must be used.
Gear Transmission:
Efficiency of power transmission in belt and rope drives is less. The power may be
transmitted from one shaft another by means of mating gears with high transmission Efficiency
and a gear drive is also provided when the between driver and follower is very small.
Chain Transmission:
Chains are used for high transmission number. They are mostly used when Distance
between center is short but the center distance is as much as 8 m. They are now generally used.
Used for transmission of power in cycle, motor vehicle, and agriculture machinery gearing in
two workshops. It is general requirement for any machines that they should provision for
regulating the speed of travel .The regulation may be available in discrete steps or it may be
steeples i.e. continuous the format are known as stepped drives Ex. Lathe machine, milling
machine, printing machine etc.

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CHAPTER 4
WORKING OF
AUTOMATIC
TRANSMISSION

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This go-kart has no gears and clutches. The transmission we use is not manual, its
automatic. For this purpose, we use continuously variable transmission. We use pulley and belt
system type CVT. This type of CVT uses pulleys, typically connected by a metal levered rubber
belt. A chain may also be used. A large pulley connected to a smaller pulley with a belt on chain
will operate in the same manner as a large gear meshing with a small gear. Typical CVTs have
pulleys formed as pairs of opposing cones. Moving the cones in and out has the effect of
changing the pulley diameter, since the belt or chain must take a large diameter path when the
conical pulleys halves are close together. This motion of the cones can be computer controlled
and driven for example, by a servomotor. However in the light weight VDP transmissions used
in automatic motor scooters and light motor cycles, the change in pulley diameter is
accomplished by a variation, an all mechanical system that uses weights and springs to change
the pulley diameters as a function of belt speed.
Figure 15: Automatic transmission
The variable-diameter pulleys are the heart of a CVT. Each pulley is made of two 20-
degree cones facing each other. A belt rides in the groove between the two cones. V-belts are
preferred if the belt is made of rubber. V-belts get their name from the fact that the belts bear the
V shaped cross-section, which increases the frictional grip of the belt. When the two cones of the
pulley are far apart (when the diameter increases) the belt rides lower in the groove, and the
radius of the belt rides lower in the groove, and the radius of the belt loop going around the
pulley get smaller. When the cones are close together (when the diameter decreases) the belt

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rides tighter in the groove, and the radius of the belt loop going around the pulley gets larger.
CVTs may use hydraulic pressure, centrifuged force or spring tension to create the force
necessary to adjust the pulley halves. Variable-diameter pulleys must always come in pairs.
Figure 16: Automatic transmission with high gear
One of the pulleys, known as the drive pulley (or driving pulley), is connected to the
crankshaft of the engine. The driving pulley is also called the input pulley because it is where the
energy from the engine enters the transmission. The second pulley is called the driven pulley
because the first pulley is turning it. As an output pulley, the driven pulley transfers energy to
drive shaft. The distance between the centers of the pulleys to where the belt makes contact in
the groove is known as the pitch radius. When the pulleys are far apart, the belt rides lower and
the pitch radius decreases. When the pulleys are close together, the belt rides higher and the pitch
radius increases.
The ratio of the pitch radius on the driving pulley to the pitch radius on the driven pulley
determines the year. When one pulley increases its radius, the other decreases its radius to keep
the belt light as the two pulleys change their radii relative to one another, they create an infinite
number of gear ratios-from low to high and everything in between. For example, when the pitch
radius is small on the driving pulley and large on the driven pulley, then the rotational speed of

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the driven pulley decreases resulting in a lower ‘gear’. When the pitch radius is large on the
driving pulley and small on the driven pulley, then the rotational speed of the driven pulley
increases resulting in a higher ‘gear’. Thus in theory, a CVT has an infinite number of ‘gears’
that it can run through at any time, at any engine or vehicle speed.
Figure 17: Automatic transmission with low gear

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Karting as a learning tool
Kart racing is usually used as a low-cost and relatively safe way to introduce drivers to
motor racing. Many people associate it with young drivers but adults are also very active in
karting. Karting is considered the first step in any serious racer's career. It can prepare the driver
for high-speed wheel-to-wheel racing by helping develop quick reflexes, precision car control,
and decision-making skills. In addition, it brings an awareness of the various parameters that can
be altered to try to improve the competitiveness of the kart (examples being tire pressure,
gearing, seat position, chassis stiffness) that also exist in other forms of motor racing. All current
as well as many former Formula One racers grew up racing karts, most(8) prominent among
them Michael Schumacher, Ayton Sienna, Alain Prost, Fernando Alonso, KimiRäikkönen and
Lewis Hamilton. Many NASCAR drivers also got their start in racing from karts, such as Darrell
Walt rip, Lake Speed, Ricky Rudd, Juan Pablo Montoya, Tony Stewart, and Jeff Gordon
Kart racing or karting
It is a variant of wheel motor with simple, small four-wheeled vehicles called karts, go-
karts, or gearbox/shifter karts depending on the design. They are usually raced on scaled-down
circuits. Karting is commonly perceived as the stepping stone to the higher and more expensive
ranks of motorsports.
Karts vary widely in speed and some (known as Super karts) can reach speeds exceeding
160 mph (250 km/h), while go-karts intended for the general public in amusement parks may be
limited to speeds of no more than 15 mph (25 km/h). A KF1 kart, with a 125 cc 2-stroke engine
and an overall weight including the driver of 150 kilograms has a top speed of 85 mph (140
km/h). It takes a little more than 3 seconds to go from 0 to 60 mph with a 125 cc shifter kart (6
gears), with a top speed of 115 mph (185 km/h) on long circuits.

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CHAPTER 5
STEERING MECHANISM

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Introduction
Primary function of the steering system is to achieve angular motion of the front wheels
to negotiate a turn. This is done through linkage and steering gear which convert the rotary
motion of the steering wheel into angular motion of the front road wheels. Secondary functions
of steering system are:
1. To provide directional stability of the vehicle when going straight ahead.
2. To provide perfect steering condition, i.e.; perfect rolling motion of the road
wheels at all times.
3. To facilitate straight ahead recovery after completing a turn.
4. To minimize tyre wear.
Requirement of a good steering system are:
1. The steering mechanism should be very accurate and easy to handle.
2. The effort required to steer should be minimal and must not be tiresome to
the drive.
3. The steering mechanism should also provide directional stability. This
implies that the vehicle should have a tendency to return to its straight ahead
position after turning
Wheel alignment:
a. Positioning of the steered wheels to achieve the following is termed wheel
alignment:
1. Directional stability during straight ahead position.
2. Perfect rolling condition on steering.
3. Recovery after completing the turn.
b. There different types of alignment can be:
1. The front-end alignment.
2. Thrust angle alignment.
3. Four-wheel alignment.

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Procedure to Wheel alignment
1. First straight the front wheels by adjusting steering wheel.
2. Then lock the steering wheel.
3. Loosen the tie rod nuts of the both side by using wrench.
4. Adjust the tie rods until the wheels vertically straight.
5. Then tighten the nuts.

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Basic steering components
99% of the world's car steering systems are made up of the same three or four
components. The steering wheel, which connects to the steering system, which connects to the
track rod, which connects to the tie rods, which connect to the steering arms. The steering system
can be one of several designs, which we'll go into further down the page, but all the designs
essentially move the track rod left-to-right across the car. The tie rods connect to the ends of the
track rod with ball and socket joints, and then to the ends of the steering arms, also with ball and
socket joints. The purpose of the tie rods is to allow suspension movement as well as an element
of adjustability in the steering geometry. The tie rod lengths can normally be changed to achieve
these different geometries.
Figure 18: Steering mechanism

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The Ackermann Angle: your wheels don't point the same direction.
In the simplest form of steering, both the front wheels always point in the same direction.
You turn the wheel, they both point the same way and around the corner you go. Except that by
doing this, you end up with tyres scrubbing, loss of grip and a vehicle that 'crabs' around the
corner. So why is this? Well, it's the same thing you need to take into consideration when
looking at transmissions. When a car goes around a corner, the outside wheels travel further than
the inside wheels. In the case of a transmission, it's why you need a differential (see the
Transmission Bible), but in the case of steering, it's why you need the front wheels to actually
point in different directions. This is the diagram from the Transmission Bible. You can see the
inside wheels travel around a circle with a smaller radius (r2) than the outside wheels (r1):
Figure 19: Angle of tyre
In order for that to happen without causing undue stress to the front wheels and tyres,
they must point at slightly different angles to the centerline of the car. The following diagram
shows the same thing only zoomed in to show the relative angles of the tyres to the car. It's all to
do with the geometry of circles:
This difference of angle is achieved with a relatively simple arrangement of steering
components to create a trapezoid geometry (a parallelogram with one of the parallel sides shorter
than the other). Once this is achieved, the wheels point at different angles as the steering
geometry is moved. Most vehicles now don't use 'pure' Ackermann steering geometry because it

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doesn't take some of the dynamic and compliant effects of steering and suspension into account,
but some derivative of this is used in almost all steering systems:
Figure 20: Steering geometry
Why 'Ackermann'?
This particular technology was first introduced in 1758 by Erasmus Darwin, father of
Charles Darwin, in a paper entitled "Erasmus Darwin's improved design for steering carriages--
and cars". It was never patented though until 1817 when Rudolph Ackermann patented it in
London, and that's the name that stuck.

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Steering ratio
Every vehicle has a steering ratio inherent in the design. If it didn't you'd never be able to
turn the wheels. Steering ratio gives mechanical advantage to the steering, allowing you to turn
the tyres with the weight of the whole car sitting on them, but more importantly, it means you
don't have to turn the steering wheel a ridiculous number of times to get the wheels to move.
Steering ratio is the ratio of the number of degrees turned at the steering wheel vs. the number of
degrees the front wheels are deflected. So for example, if you turn the steering wheel 20° and the
front wheels only turn 1° that gives a steering ratio of 20:1. For most modern cars, the steering
ratio is between 12:1 and 20:1. This coupled with the maximum angle of deflection of the wheels
gives the lock-to-lock turns for the steering wheel. For example, if a car has a steering ratio of
18:1 and the front wheels have a maximum deflection of 25°, then at 25°, the steering wheel has
turned 25°x18, which is 450°. That's only to one side, so the entire steering goes from -25° to
plus 25° giving a lock-to-lock angle at the steering wheel of 900°, or 2.5 turns (900° / 360).
This works the other way around too of course. If you know the lock-to-lock turns and the
steering ratio, you can figure out the wheel deflection. For example if a car is advertised as
having a 16:1 steering ratio and 3 turns lock-to-lock, then the steering wheel can turn 1.5x360°
(540°) each way. At a ratio of 16:1 that means the front wheels deflect by 33.75° each way.
For racing cars, the steering ratio is normally much smaller than for passenger cars - i.e. closer to
1:1 - as the racing steering need to get fuller deflection into the steering as quickly as possible.

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Turning circles
The turning circle of a car is the diameter of the circle described by the outside wheels
when turning on full lock. There is no hard and fast formula to calculate the turning circle :
turning circle radius = (track/2) + (wheelbase/sin (average steer angle))
The numbers required to calculate the turning circle explain why a classic black London taxi has
a tiny 8m turning circle to allow it to do U-turns in the narrow London streets. In this case, the
wheelbase and track aren't radically different to any other car, but the average steering angle is
huge. For comparison, a typical passenger car turning circle is normally between 11m and 13m
with SUV turning circles going out as much as 15m to 17m.
Steering system by pitman arm system:
There really are only two basic categories of steering system today; those that have
pitman arms with a steering 'box' and those that don't. Older cars and some current trucks use
pitman arms, so for the sake of completeness, I've documented some common types. Newer cars
and unit body light-duty trucks typically all use some derivative of rack and pinion steering.
Pitman arm mechanisms have a steering 'box' where the shaft from the steering wheel
comes in and a lever arm comes out - the pitman arm. This pitman arm is linked to the track rod
or centre link, which is supported by idler arms. The tie rods connect to the track rod. There are a
large number of variations of the actual mechanical linkage from direct-link where the pitman
arm is connected directly to the track rod, to compound linkages where it is connected to one end
of the steering system or the track rod via other rods. The example below shows a compound
link.

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Figure 21: Pitman arm Steering mechanism
Most of the steering box mechanisms that steering the pitman arm have a 'dead spot' in
the centre of the steering where you can turn the steering wheel a slight amount before the front
wheels start to turn. This slack can normally be adjusted with a screw mechanism but it can't
ever be eliminated. The traditional advantage of these systems is that they give bigger
mechanical advantage and thus work well on heavier vehicles. With the advent of power
steering, that has become a moot point and the steering system design is now more to do with
mechanical design, price and weight. The following are the four basic types of steering box used
in pitman arm systems.
Worm and sector
In this type of steering box, the end of the shaft from the steering wheel has a worm gear
attached to it. It meshes directly with a sector gear (so called because it's a section of a full gear
wheel). When the steering wheel is turned, the shaft turns the worm gear, and the sector gear
pivots around its axis as its teeth are moved along the worm gear. The sector gear is mounted on
the cross shaft which passes through the steering box and out the bottom where it is splined, and

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the pitman arm is attached to the splines. When the sector gear turns, it turns the cross shaft,
which turns the pitman arm, giving the output motion that is fed into the mechanical linkage on
the track rod. The following diagram shows the active components that are present inside the
worm and sector steering box. The box itself is sealed and filled with grease.
Figure 22: Worm and sector
Worm and roller
The worm and roller steering box is similar in design to the worm and sector box. The
difference here is that instead of having a sector gear that meshes with the worm gear, there is a
roller instead. The roller is mounted on a roller bearing shaft and is held captive on the end of the
cross shaft. As the worm gear turns, the roller is forced to move along it but because it is held
captive on the cross shaft, it twists the cross shaft. Typically in these designs, the worm gear is
actually an hourglass shape so that it is wider at the ends. Without the hourglass shape, the roller
might disengage from it at the extents of its travel.

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Figure 23: Worm and roller
Worm and nut or recirculating ball
This is by far the most common type of steering box for pitman arm systems. In a
recirculating ball steering box, the worm steering has many more turns on it with a finer pitch. A
box or nut is clamped over the worm steering that contains dozens of ball bearings. These loop
around the worm steering and then out into a recirculating channel within the nut where they are
fed back into the worm steering again. Hence recirculating. As the steering wheel is turned, the
worm steering turns and forces the ball bearings to press against the channel inside the nut. This
forces the nut to move along the worm steering. The nut itself has a couple of gear teeth cast into
the outside of it and these mesh with the teeth on a sector gear which is attached to the cross
shaft just like in the worm and sector mechanism. This system has much less free play or slack in
it than the other designs, hence why it's used the most. The example below shows a recirculating
ball mechanism with the nut shown in cutaway so you can see the ball bearings and the
recirculation channel.

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Figure 24: Worm and recirculating ball
Cam and lever
Cam and lever steering boxes are very similar to worm and sector steering boxes. The
worm steering is known as a cam and has a much shallower pitch and the sector gear is replaced
with two studs that sit in the cam channels. As the worm gear is turned, the studs slide along the
cam channels which forces the cross shaft to rotate, turning the pitman arm. One of the design
features of this style is that it turns the cross shaft 90° to the normal so it exits through the side of
the steering box instead of the bottom. This can result in a very compact design when necessary.

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Figure 25: Cam and lever
Steering system by rack &pinion:
This is by far the most common type of steering you'll find in any car today due to it's
relative simplicity and low cost. Rack and pinion systems give a much better feel for the steering,
and there isn't the slop or slack associated with steering box pitman arm type systems. The
downside is that unlike those systems, rack and pinion designs have no adjustability in them, so
once they wear beyond a certain mechanical tolerance, they need replacing completely. This is
rare though.
In a rack and pinion system, the track rod is replaced with the steering rack which is a long,
toothed bar with the tie rods attached to each end. On the end of the steering shaft there is a
simple pinion gear that meshes with the rack. When you turn the steering wheel, the pinion gear
turns, and moves the rack from left to right. Changing the size of the pinion gear alters the
steering ratio. It really is that simple. The diagram below shows an example rack and pinion
system as well as a close-up cutaway of the steering rack itself.

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Figure 26: Rack and Pinion

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