Coil Springs | Replace in Pairs
Automotive suspension springs are a central and dynamic component of a vehicle’s suspension system, constantly working to absorb shocks and deal with uneven road surfaces. After many millions of cycles, even the best made springs may break or become tired and begin to sag, causing the vehicle ride height to become uneven.
When this happens, garages too often replace just the defective spring rather than an axle pair. Failure to replace in pairs can have multiple negative consequences, conceivably costing significantly more than just the price of an extra spring.
Coil springs across an axle degrade at around the same rate during normal use, as they are exposed to the same conditions, meaning that when one sags or breaks (if both were fitted at the same time) the other will not be far behind.
Replacing in pairs will return a vehicle to its original ride height and comfort. However when just one spring is replaced, an imbalance will most likely be created resulting in an uneven ride. This can lead to more stress being exerted on the spring that has not been replaced, reducing its life expectancy.
Since coil springs are so central to the overall handling of a vehicle, the imbalance resulting
from a failure to replace in pairs can cause multiple significant safety risks. These include:
LESS RESPONSIVE STEERING
The older spring cannot effectively transfer weight to the other springs during cornering, especially if it has been weakened or begun to sag. This leads to increased body roll in bends.
LESS SECURE ROAD HOLDING
During cornering, a sagging spring will experience increased compression, but with less stored mechanical energy available to keep the vehicle balanced and transfer weight evenly. This will introduce a ‘lean’ during cornering which can adversely affect road holding.
INCREASED BRAKING DISTANCE
During braking, more of the vehicle’s weight transfers from the rear tyres to the front tyres, causing the nose to dip forward (known as ‘dive’). Uneven balance across the front axle can occur under braking, potentially increasing stress on the spring that has not been replaced. This in turn will reduce the friction on the other tyres and increase the distance required to stop.
INCREASED TYRE WEAR
Increased pressure is exerted upon the tyre where the spring has not been replaced, leading to faster wear and eventually a bill for new tyres – potentially many times the cost of a coil spring.
It is therefore important for workshops to encourage customers to replace springs in axle pairs, just as they would with brake pads or discs. By replacing in pairs, the customer actually makes a cost saving, as the labour to replace two springs during the same job will be cheaper than the labour for replacing individual springs twice within a short period. Not to mention the inconvenience of repeatedly having the vehicle off the road!
Lesjöfors produce the world’s largest range of coil springs, featuring more than 10,000 applications covering the majority of European and Asian vehicles on the road today.