LEAF vs COIL SPRINGS

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The leaf versus coil debate has been going on since Land Cruiser 70 Series drivers got jealous of the comfy ride in coil-sprung Land Rover Defenders. We joke, but both leaves and coils have a range of benefits and drawbacks that suit different vehicles and needs. How you value these attributes could affect your next choice of vehicle…

The task at hand

Your vehicle’s suspension system is possibly the hardest-working, least understood, most abused and undermaintained aspect of your rig. The average bakkie is expected to safely carry a ton, but remain comfortable and stable when empty on the school run. Suspension needs to be flexible enough over rough terrain to keep all four wheels planted while in an axle twister, but at the same time contain body roll when speeding along a twisty mountain pass. The fact is, a relatively simple arrangement of springs and shock absorbers must cope with a huge variety of situations while still being reliable, safe, and cheap to produce.

These are among the reasons compromises must be made by manufacturers, because no standard suspension system can be perfect for everybody.

It’s also why there is such a thriving aftermarket for upgraded suspensions. But, dialling back, why do some manufacturers use leaves and others coils? Why are most modern bakkies fitted with coils in the front but retain leaves in the back? And what are the fundamentals of these systems?

LEAF SPRINGS

An incredibly simple solution that’s been doing duty since the first sprung wheeled vehicle appeared, is that leaf springs consist of a stack of semi-elliptical (curved) spring steel plates. These are connected at their centre to an axle and suspended from