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1. SUSPENSION
• A vehicle runs on different types road
conditions such as even, uneven, rough
etc.
• To isolate the passengers and other
vehicle components from the
irregularities of road surface, the vehicle
chassis is not directly mounted on the
axles.
• Spring or suspension system is
mounted between the passenger
compartment and axle to isolate the

2. Objectives of suspension:
 To safeguard the passengers against
the road shocks and provide riding
comfort.
 To prevent the road shock from being
transmitted to vehicle frame and other
components.
 Maintain stability of the vehicle by
minimizing the effect of rolling and
pitching.
 To support vehicle weight.

3. Leaf spring/ conventional
suspension

4.  Leaf springs are the most traditional
type of suspension system.
 They are used for light,medium and
heavy commercial vehicles.
 Leaf spring consists of following major
components:
 Leafs
 Clamps
 Shackle
 U-Bolt

5. Independent Suspension
 In independent suspension, all the
road wheels are so connected to the
frame that rise and fall of any wheel
has no effect on the other.

6. Wishbone Type Suspension

8. Wishbone type Independent
Suspension
 It consists of upper wishbone and lower
wishbone.
 A coil spring with shock absorber placed
inside it, is mounted between the wishbone
structure.
 Upper and lower wishbone arm are pivoted
to the cross member of vehicle frame.
 The vehicle weight is transferred from :
Vehicle frame cross member coil spring Lower
wishbone
 This suspension resists up and down forces
developed after bump, acceleration, braking,
cornering.

9. Macpherson Strut Suspension:

10. Mac-Pherson……
 Mac Pherson suspension consists of a strut
containing shock absorber on one side.
 The strut is connected to the stub axle and
wheel.
 It consists of lower wishbone arm which is hinged
to the frame cross member.
 The load is transferred from the body member to
spring strut to stub axle and lower wishbone arm.
 This system is simpler than wishbone type and
also reduces the unsprung weight.
 This system provides maximum space in engine
compartment.
 It is most commonly used on all front wheel drive
cars.

11. Air Suspension

12.  Air suspension works on the principle
of allowing or restricting the passage
of compressed air through a small
orifice.
 They are often used in heavy load
carrying vehicles requiring smooth
suspension such as luxury buses.
 The air suspension system consists of
4 air bags or bellows that support the
sprung weight on the frame of vehicle.

13. Working
 The air compressor sucks in
atmospheric air through filter and
pressurizes it.
 Compressed air is stored in
accumulator and can be withdrawn as
per requirement.
 If the pressure in accumulator
exceeds a predetermined value, the
air safety valve opens to bypass
excess air.

14. Working…
 The high pressure air passes to leveling
valve via lift control valve
 When the vehicle comes across a bump,
based on the deflection of a particular air
bellow, the leveling valve pumps in more
air in that bellow.
 the compressed air in the bellow or bag
absorbs the vertical up and down
vibrations.
 Any excess air in the bellow can be
released back by leveling valve in the
pipeline.

15. Advantages:
 It ensures constant vertical height
irrespective of road surface.
 It has constant frequency of vibration
rather than metal springs which
oscillate more rapidly.
 It provides excellent ride comfort and
noise reduction.

16. Limitations:
 It offers high flexibility. Hence to
improve the stiffness, air suspension
is generally equipped with additional
shock absorbers.
 Failure of air compressor causes
failure of entire suspension system.

17. Tyres: A tyre is a band of layers of iron ,
steel , rubber etc. mounted on the rim of
a wheel and transmit the load and power
to the road.

18. Desirable properties of tyre:
 It should be strong enough to transmit vehicle
load to the road.
 It should be balanced, both statically and
dynamically.
 It should not wear away at the surface after
long usage.
 It should have adequate friction to roll on
different types of road surface.
 It should be light in weight to reduce
unsprung weight.
 It should be easily accessible for removing
and mounting.

19. Conventional Tubed Tyre:

20. Components of tyre:
 Tyre
 Tube
 Bead
 Carcass
 Tread
 Valve

21. Tubeless Tyre:

22. Tubeless Tyre:
 Tubeless tyre is an advanced version
of conventional tubed tyre.
 The tubeless tyre does not need
separate inner tube.
 The tyre have a special air retaining
bead arrangement.
 The tyre is directly mounted on rim
and retains the air.

23. Avantages of tubeless tyre:
 Improved safety
 Ease of puncture repair
 Slow leakage of air
 Simple assembly
 Better cooling
 Lesser unsprung weight

24. Radial Ply & Cross Ply Tyre:

25. Factors affecting tyre life:
 Inflation
 Vehicle maintenance
 Driving manners
 Miscellaneous factors (like
overloading, higher atmospheric
temperature, road condition etc.)

26. Wheel alignment
Positioning of steered wheel to achieve
the following is called wheel
alignment:
1.Directional Stability
2. Perfect rolling condition on steering
3. recovery after completing turn

27. Factors of wheel alignment
 Factors pertaining to wheel:
Balance of wheels, Inflation of tyres,
Brake adjustment
 Steering geometry
Castor, Camber, King Pin Inclination,
Toe-In, Toe-out
 Steering Linkages
 Suspension

28. Wheel Balancing
 Static balancing
 Dynamic balancing