wheel and tire system in automotive

1. Tire and Wheel

2. Contents
 Introduction
 Functions' of tire
 Types of tire
 Wheel balance
 TPMS

3. Introduction
What percent of a tire is rubber?
 Composition of tire
 Raw Rubber
 Steel
 Nylon
 Polyester
 Rayon
 Carbon Black
 Synthetic Rubber
 Fiberglass
 Aramid
 Brass

4. Cond’t…
 Who InventedThe First Tire?
 It was invented in 1888, by
John Dunlop.
 This would be the end of
the solid tire.
Why are Tires Black?
To protect the rubber from the
harmful UV rays.
A common type of UV stabilizer
called a competitive absorber is
added to capture and absorb
these harmful UV light wave
energy.
All use the same competitive
absorber, carbon black.

5. Functions' of tire
 Supports the vehicle load
 Act as primary suspension
 Provide frictional contact with the road
 Front tires allow the wheel to steer
 Allows braking to slow or stop the
vehicle
 It develops longitudinal force for acceleration and
braking and It develops lateral force for cornering

6. Properties of tire
 Non- skidding
 Uniform wear
 Load caring capacity
 Speed capacity
 Cushioning
 Noise
 balance

7. Tire construction

8. Carcass (casing)
 The carcass is the framework of the tire.
 It consists of layer of tyre cords bonded
together with rubber.
 It must be rigid enough to hold in the high
pressure air, yet flexible enough to absorb
load changes and impact.

9. Tread
 Is an external rubber layer protecting the
carcass from wears and external damage
caused by the road surface
 It is the part that directly contacts the road and
generates the tractive resistance that transmits
the vehicles driving and braking forces to the
road.
 The tread pattern consists of grooves moulded
into the tread surface, and is designed to help
the tire more effectively transmit these forces
to the road

10. Side Walls
 The side walls are rubber layer that
cover the sides of the tire and protect
the carcass from external damage.
 They bear the manufacturer's name, tire
size, and other information.

11. Tire ratings and side wall information
 Includes the following information:
 tire type
 section width
 aspect ratio
 construction type
 rim diameter
 load capacity, and
 speed symbol

14. Types of tire
Tube tire Tubeless tire

15. Cond’t…
 There are two main types of tires
available on the market today
Bias Ply tires and
Radial Ply tires.

16. Bias-ply tires (oldest design)

17. Cond’t…
• The layers (built with 2 to 4 plies) run in opposite
directions.
i.e The angle is reversed from ply to ply.
• Cords are not woven like ordinary cloth.
 Because that would lead to rubbing of the two
layers and thus produce heat which would damage
the tyre material.
 The tread is bonded directly to the top ply because
it does not use belts.

18. ... Bias ply characterstics
• Allows the body of the tire to flex easily.
This tends to improve cusioning action.
Gives a smooth ride on rough roads.
• The greater the cord angle,
the softer the carcass becomes.
The lower its lateral stability.

19. Radial ply type
• the ply cords run in the radial direction i.e, in the
direction of the tyre axis.

20. Cond’t…

21. Cond’t…

22. Cond’t…

23. Wheel rim purpose
 Can be manufactured from steel, cast
aluminum, forged aluminum, pressure
cast chrome-plated aluminum, or
magnesium alloy
 Wheel rim must retain the tires safely
under all operating conditions without
distortion.

24. Wheel rim…
 Tire and wheels must form air-tight
containers at all temperatures so air
does not leak from the assembly
 Wheel rims must position the tires at
the proper distance inward or
outward from the vertical mounting
surface of the wheel.

25. Rim offset
 Is the distance from the hub mounting
surface to the center line of the wheel.
 The rim offset affects front suspension
loading and operation.
 Measured in millimeters and results in
a positive, negative, or zero offset

27. Rim offset…
 Positive rim offset is mostly used
on front-wheel drive cars and
newer rear-drive vehicles
 Negative rim offset is mostly found
on trucks and off-road vehicles

28. Static wheel balance
 With proper static balance, weight is equally
distributed around its axis of rotation,
 So, gravity will not force it to rotate from its
rest position
 Gravity acting on this heavy portion will
cause the wheel to rotate until the heavy
part is located near the bottom of the tire

29. Results of static unbalance
 Centrifugal force attempts to move the
heavy spot on a tangent line away from the
wheel axis.
 This action tends to lift the wheel assembly
off the road surface
 Also referred to as wheel tramp
 This action causes severe tire scuffing and
cupping

30. Static unbalance…
 This action causes rapid wear on
suspension and steering components
 Passenger discomfort and driver fatigue

31. Static unbalance…

32. Dynamic wheel balance
 The weight is distributed equally on both
sides of the wheel center viewed from the
front
 If A&C are equal then B&D should also
equal in weight

33. Dynamic unbalance
 If a tire has dynamic unbalance, section
D may have a heavy spot; thus, sections
B&D have different weights
 Centrifugal force moves the heavy spot
toward the tire centerline
 causes lateral wheel shake, or shimmy

34. Results of dynamic unbalance
 This action causes steering wheel
oscillations at medium and high speeds
with resultant driver fatigue and
passenger discomfort
 Also cause unstable directional control of
the vehicle

35. Dynamic unbalance

36. Dynamic unbalance..
 heavy spot at the rear of the left front tire

37. Purpose of wheel balance
 Maintains normal tire tread life.
 Provides extended life of suspension and
steering components.
 Helps provide directional control of the
vehicle.
 Reduces driver fatigue.
 Increases passenger comfort.
 Helps maintain the life of body and
chassis components.