Changing the ride height on a truck or trailer air suspension can be a quick gain, which can lead to maximum pain. The adjustment may be a quick fix for a drive line angle issue or reaching a certain king pin height on a trailer. Unfortunately, these quick fix changes may eventually lead to some expensive headaches in the future.
Over the past 30 years Powerdown reckons it has had many calls about suspension related issues. One of the most common is related to the ride height of rear air or trailer suspensions which have been adjusted above the OEM (Original Equipment Manufacturers) recommendations. This change in ride height can cause damage to the suspension equipment.
A shock absorber is primarily designed to operate in the midpoint of the extended and compressed length of the unit. By increasing the ride height of the suspension, the suspension droop is reduced which limits the downwards travel available in the shock absorber.
This dramatically increases the likelihood of the damper topping out when the suspension articulates. The piston could then effectively hit the top guide of the shock absorber causing fatigue issues in the design.
A re-coil cut off or rebound stop can limit some of the damage in the short term, but this feature is not designed for continual topping out of the unit. This can also lead to premature bush failure and other related end fitting damage.
Eventually, over time, the shock absorber will most likely leak oil due to internal damage from the constant impact. In extreme cases the life of the shock absorber can be reduced by 80 per cent of its normal service life.
Short stroke shock absorbers on trailers and some rear drive air suspensions are more susceptible than others.
In an industry first Powerdown says it has released a range of shock absorbers with a recommended ride height sticker. This sticker is designed to indicate where the shock absorber is operating in terms of stroke when the shock absorber is fitted to the vehicle.
The sticker is strategically placed on the body of the shock absorber to indicate shock absorber stroke relative to vehicle ride height.