One shock is enough

COMMENT

I’ve crawled under more than a few camper trailers and off-road caravans over the past 15 years and during that time have seen an evolution in suspensions that's quite mind boggling.

Single and double cross body axles of old, have been gradually fading from the market, ceding to roller rocker springs which in turn are being overtaken by independent swing arm systems in trailers other than work box trailers and including low-end camper trailers and non off-road caravans.

A variety of dampening features such as springs, air bags and combinations of those two, along with shock absorbers in single and double installation per wheel are all the rage of late.

Why pairs?

Shock absorbers are generally installed on off-road chassis as stand-alone or as a pair per wheel. Typically these use gas or oil-filled barrels with plungers and valves with fixed or manually adjustable settings.

Some up-market systems are attached to gas reservoirs that may be manipulated remotely and purport to offer a better ride over their competition. Being able to adjust to your travelling conditions whilst on the run has its advantages.

Not often seen in the RV market are specialised dual set shock absorbers, where one operates on compression whilst the other on the same swinging arm operates on the rebound. This style of shocker is more commonly seen on two and four-wheeled vehicles at extreme rallies such as the Dakar.

Keep it simple

So is more the better? Maybe but here are a couple of points to think about.  Firstly, engineering a chassis to take more than two shock absorbers is going to come at an increased cost due to extra man hours and base materials.

Also worth considering is the cost of the additional units themselves -- another drain to the back pocket. Given two shockers might cost $360, four smaller units capable of doing the same job won’t be double that, but don’t be surprised if the till rings at around 75 per cent higher than a two shock set-up.

I based these figures on a quick ring around to a couple of the major off-road shock absorber manufacturers.

There's also false security in relying on a survivor of a twin shocker set on one wheel to get you home over rough country after its partner has failed. Each shock in the set is typically lighter duty than a single, and with one failing or totally unserviceable, double the stress on the remaining shock won't extend its life, if you know what I mean...

For my off-road money, a single shock absorber at each wheel -- like you see under many premium Aussie off-road camper trailers -- and one spare in the parts boot is the go.