cc 65 tire and suspension

7/30/2019 CC 65 Tire and Suspension

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Goodheart-Willcox Co. Inc.


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Tires perform two basic functions:

act as a soft cushion between the road

and the metal wheel

provide adequate traction (friction) with

the road surface


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Tire Types

Pneumatic

filled with air

internal air pressure pushes out on the

inside of the tire to support the vehicle Tubeless tire

does not use an inner tube

tire and wheel form an airtight unit

Tube-type tire

uses an inner tube to hold air pressure


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Radial Ply Tire

Uses a very flexible sidewall with a stiff

tread

provides a very stiff footprint

improves safety, cornering, braking, and

wear

may produce a harsher ride at low speeds


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Radial Ply Tire


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Tire Sidewall Markings


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Tire Size

P= passenger

LT=Light Truck

ST= Special Trailer

T= Temporary

C= Commercial


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Points of Measurement


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Aspect Ratio

Height-to-width ratio of a tire. Comparison

of a tires height and width


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Tread Plies

Number of plies and ply rating:

2-ply

2-ply with a 4-ply rating 4-ply

Ply rating doesnt mean how many

plies the tire hasPlies are made of different materials

today


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Maximum Load RatingAmount of weight the tire can carry at

the recommended inflation pressure

Printed on the sidewall

P-metric:

given in kilograms and pounds

Alpha-numeric: indicated by a letter such as B, C, or D


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Maximum Inflation

Pressure Highest air pressure that should be

pumped into the tire

Many tires have a maximum

recommended pressure of 32 to 40 psi

(220 to 275 kPa)

Ch ki Ti I fl i



Checking Tire InflationPressure

Check the manufacturesrecommended tire pressure

In Door Jam

In owners manual

Compare to max inflationand inflate to proper inflation

Many of today's cars have to be

inflated to manufactures specs



Tire Inflation Pressure



Speed RatingMaximum allowable sustained road

speed a tire can safely withstand

without failure



Traction Rating

Traction rating is a letter based on a

straight-line wet surface braking test

AA- (Best)

A

B

C- (Worst)



Tread Wear

Higher the number the better the tread

wear

Tread wear rating 200 will last 2 times aslong as a 100

Can not compare differentmanufactures tread wear ratings



Heat Rating

A- Best (coolest running tire)

B-

C- Least able to dissipate heat



Wear Bars

When too much

tread has wornaway, solid rubberbars will show upacross the tread



Tread Depth

Checking tread depth

Min depth allowed is 2/32



Rotating Tires

Ensures maximum tire life

Front and rear tires wear differently

Rotation helps even out tire wear

Tires are rotated at intervals such as

every 3000 miles (5000 km)



Rotation Patterns



Tire Rotation Dually



Todays Preferred Pattern

This Pattern is used todaybecause of radial tire

memory!



Compact Spare Tire

This is a high pressure spare, requiring

60 psi (415 kPa)



Self-Sealing Tire

ActionA. Nail punctures tire

B. Nail is pulled out

C. Sealing compound

flows into the hole



Run-Flat Tires

Use extremely stiff sidewall

construction

Still usable with a loss of air pressure

Tire will still retain most of its shape

because the sidewall is strong enough

to support vehicle weight



Run-Flat Tires



Tire Inflation

Monitoring SystemOften used with run-flat tires

Pressure sensors are mounted on each

wheel

If tire pressure is not correct, the wheel

sensor produces a radio signal

Signal is received by a module thatturns on a dash warning light



Pressure Sensor


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System Operation


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ABS Tire Monitoring

Wheel speed ismeasured using ABS

sensors

Different wheel speeds

equals uneven tire

pressures


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Valve Stem Assembly

Valve stem snapsinto the hole

in the wheel

Press fit formsan airtight seal

Valve corescrews into the

valve stem body


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Lug Nut

and StudStud is pressed

into the hub oraxle flange

If metric or left-handthreads are used,

markings willnormally be given


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Torquing Lug Nuts

Torque is very important, especially on

vehicles with mag wheels and

lightweight hubs

Overtorquing can cause wheel and hub

distortion, or brake pulsation

Undertorquing might allow the lug nuts

to loosen and the wheel to fall off


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Wheel Cover Removal

Pry between the wheel and cover

at four alternating points


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Wheel Cover Installation

Hold the wheel cover in place with the

valve stem sticking through the cover


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Wheel balance is a common cause oftire and steering wheel vibration

When one side of a tire is heavier than

the other, centrifugal force tries tothrow the heavy side outward when the

tire is rotating


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Supports the weight of the vehicle

Allows the wheels to move up anddown

Allows rapid cornering without extreme

body roll Keeps the tires in firm contact with the

road


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Suspensions

Independent

Nonindependent


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Types of Springs

A. Coil spring

B. Leaf springC. Air spring

D. Torsion bar


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Coil Springs


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Leaf Spring Assembly


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Air Springs


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Torsion Bar

The bar resists twisting action and acts

like a conventional spring


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Ball Joints

Tapered stud provides a force fit into the

steering knuckle or bearing support

Sh k Ab b


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Shock AbsorberAction


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Checking Shock

Absorber Condition Perform a visual inspection fordamage, rubber bushing wear or oil

leakage Perform a shock absorber bounce test

push down on one corner of the vehicle

release the body count the number of times the body

rebounds

maximum two or three oscillations


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Sway Bar(Stabilizer Bar)

Sway bar links connect the bar

to the control arms


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Front Suspension

(MacPherson Strut)


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Strut Compressor


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Provide precise control of the wheel

directionMaintain correct steering effort

Transmit road feel to the drivers hands

Absorb most of the road shock going tothe steering wheel

Allow for suspension action


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Two basic kinds of steering systems

are in use today:

Parallelogram steering systems rack-and-pinion steering systems

Each may be operated manually or with

power assist


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SteeringParallelogram

Steering

Basic Rack-and-

Pinion Steering

Parallelogram Steering


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57

Parallelogram SteeringSystem

Fig. 2-5

Credit: ATW Assembly & Test Worldwide

Rack-and-Pinion Steering


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58

Rack and Pinion SteeringSystem

Fig. 2-7

Credit: ATW Assembly & Test Worldwide


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Steering Rack

(Rack and Pinion Steering)


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Steering Gear box

(parallelogram steering)


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Basic Power Steering


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Steering Wheel Play

Amount that you can turn the steering

wheel without front wheel movement

Caused by worn ball sockets, a wornidler arm, or too much clearance in the

steering gearbox

Compare the play to service manual

specifications

e.g. 1 1/2 (33 mm)


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Dry Park Test

With the vehicle on the ground, rotate the

steering wheel back and forth while

someone watches for part wear

St i I ti


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Steering Inspection

Raise the vehicle on a lift. Wiggle the

tires back and forth while watching

for steering play


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Maintenance involves checking for lowfluid level, incorrect belt adjustment,

system leaks, and other problems

Ball socket lubrication may benecessary


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Checking the Fluid

Check most systems at operating

temperature, with the engine off


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Tire Problem

Under-inflated Tire


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Tire Problem

Over-inflated Tire


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Tire Problem

Cupping

Out of balance

Lack of proper

rotation

Broken belts in tire


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Tire Problem

Alignment Problem

Worn Parts

Bent Parts


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Alignment

Three Angles to check Camber

Caster

Toe

Camber


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Camber

Positive camberTire leans away

from vehicle

Negative camberTire leans

towards vehicle

Causes tire wear

Causes vehicle

pulling


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73

Camber


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CasterAmount of upper

and lower ball

joint offset

Will causevehicle pull

Does not cause

tire wear


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75

Caster


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Toe

measurement

difference across

front and back of tiresWill cause tire wear

Will result in pulling or

wandering


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77

Toe Angle


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Tire Future

Tweel

Pneumatic tire

Michelin

Experimented with

in Military and Off

Road applications

Tire Future


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Tire Future

cc 65 tire and suspension

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