Suspension modifications

Many vehicle owners feel that it is necessary to fit stronger springs to the back of their car or 4WD in order to tow a caravan. The justification is that the back of the car goes down when the caravan is lowered on the towball. If the vehicle is a few years old and the springs have sagged a little then replacing the springs may be a worthwhile modification.

However if the only reason the suspension height alters is the weight of the van, then a weight distribution hitch is needed to take care of this, not stronger springs.

There are two cases where suspension modifications may be desirable or necessary. These involve additional loads in the vehicle that cause the vehicle height to reduce before the van is hitched on. If there is a constant additional load as, for example, in the case of an after-market LP gas conversion, then stronger springs may be needed to bring the vehicle back to its normal unladen height. In the case of occasional extra loads like camping gear, then air-adjustable shock absorbers or air bags are most suitable. After the vehicle is loaded, air pressure can be adjusted to restore the original height. Air adjustable shock absorbers or airbags should not be used to compensate for weak springs or to support the weight of the caravan.

All shock absorbers on the towing vehicle should be in good condition to help prevent pitching or instability while towing. Good shock absorbers not only improve the handling of a vehicle but also increase tyre life.