This document summarizes a leaf spring suspension system. It discusses that leaf springs are commonly used for heavy duty vehicle suspensions and are one of the oldest spring forms. The document outlines the typical dimensions and materials used for leaf springs. It then provides step-by-step instructions for replacing leaf springs and discusses advantages like simplicity and reduced weight, as well as disadvantages like reduced ride comfort over time. Finally, it notes that leaf springs are well-suited for commercial vehicles that need to support large vertical loads.

1. AEN LCA 5
Leaf spring suspension
Name : Aamin Rabkavi
Atul Arkhade
Adwait Vartak
Prathmesh Kulkarni
Under Guidance of Prof Ketan Karandikar

2. Introduction
 A leaf spring is a simple form of spring, commonly used for the
suspension in heavy duty vehicles.
 It is also one of the oldest forms of spring, dating back to medieval
times.
 The center of the arc provides location for the axle, while tie holes
are provided at either end for attaching to the vehicle body.
 For very heavy vehicles, a leaf spring can be made from several
leaves stacked on top of each other in several layers, often with
progressively shorter leaves.
 Leaf springs can serve as damping to some extent as well as
springing functions.
 For this reason manufacturers have experimented with mono-leaf
springs.

3. Cont..
 The standard dimensions for the width and thickness of the leaves
section are as follows:
 Nominal thickness :- 3.2, 4.5, 5, 6, 6.5, 7, 7.5, 8, 9, 10, 11, 12, 14.
 Nominal width (mm) :- 32, 40, 45, 50, 55, 60, 65, 70, 80, 90, 100 and 125.
 The leaves are usually made up of steels.
 The factor of safety based on the yield strength is form 2 to 2.5 for
the automobile suspension.

4. Nomenclature

5. Types

6. Tools Required
 2 replacement leaf springs
 Ratchet wrench
 Floor jack
 2 jack stands
 Penetrating oil
 Pliers
 Pry bar

7. Assembly
Step 1 :
Raise the rear
wheels with a
floor jack

8. Step 2 :
Place jack
stands in front
of the back
tires.

9. Step 3 :
Push the car
with your hand
to make sure it
is stable.

10. Step 4 :
Use safety
glasses & soak
the spring’s
nuts and bolts
in oil

11. Step 5 :
Remove the
bolt from the
shock pads
with a ratchet
wrench

12. Step 6 :
Loosen theU-
bolts to
remove them

13. Step 7 :
Unscrew the
eyelet bolts on
the spring’s
ends

14. Step 8 :
Repeat the
steps to
remove the
other leaf
spring

15. Step 9 :
Position the
new leaf spring
under the
mounting
brackets

16. Step 10 :
Screw the leaf
spring to the
front bracket
with a ratchet
wrench.

17. Step 11 :
Attach the
spring to the
rear bracket

18. Step 12 :
Install theU-
bolts and
shock pad

19. Step 13 :
Secure the
other leaf
spring to the
opposite tire

20. Step 14 :
Remove the
floor jack and
you are done

21. Advantages
 The way the suspension is constructed is really simple and strong,
acting as a linkage that holds the axle in position without the need
for separate linkage.
 Extra weight and costs are reduced because of the rear axle
location.This eliminates the need for trailing arms and a panhard
rod (AKA track bar).
 Leaf springs support the weight of the chassis, making them ideal
for commercial vehicles.
 They also control axle damping.
 The chassis roll can be controlled more efficiently due to the high
rear moment centre and wide spring base. If the springs are
mounted wider apart, the roll tendencies will be less.

22. Disadvantages
 They aren’t always the easiest to install – but there is a clear
process to follow that makes life much easier.
 The ride comfort isn’t as great because of the inter-leaf friction
between each leaf.
 Over time, the springs tend to lose shape and can sag.When the
sag is uneven, it can alter the cross weight of the vehicle which can
affect the handling slightly.This can also change the axle-to-
mount angle.
 Wind-up and vibration can be caused by acceleration and braking
torque.The wind-up can also cause nose-diving and rear-end
squat.

23. Why choose
leaf springs?
 Large layers of metal are what make up the
basic anatomy of a leaf spring, meaning they
can deal with huge vertical loads.
 They offer a huge amount of support between
the wheels, axles and the vehicles chassis,
making them perfect for commercial vans,
pickups, trailers and trucks, where the need to
support greater weights is essential.

24. Applications

25. ThankYou