Air suspension for Offroad Caravans & Campers: Diamonds in the Rough

Posted by Bruce Loxton

Nov 21, 2014 5:24:00 PM

A diamond in the roughTravelling to the best parts of Australia, you will need to enjoy the ride... literally. Air suspension on offroad camper trailers and caravans is just the easiest way to do this.

One of the benefits of air suspension is adjusting the ride height for different conditions. Later in this article you can see a short video clip of the air suspension on a Kimberley Kamper Platinum model set at three different heights. Setting the suspension low while on the main highways pulls the unit close to the road with improved fuel consumption. More importantly, it is just easier to tow.

When travelling through water crossings or difficult terrain, you can increase the height significantly without an impact on ride quality.

air bag suspensionIf you are travelling with the maximum water capacity that can be carried on board, the tare weight of just over a tonne will increase by 210kgs. With air suspension, you can lift the height to compensate for added weight.

There is a good reason why computer delivery vans have air-suspension. The soft ride internally protects the valuable goods on board. And this is only around city roads. So when travelling on country roads, air suspension will let your unit glide over the rough and protect your food and belongings.

Have you ever followed a caravan that is jumping all over a corrugated roads at 30-40klms/hr? Is it the suspension, the weight, or just a shocking road? Probably all three!

Most offroad caravans with coil or leaf spring suspension have the dimmema of increasing the stiffness of the springs to carry a higher weight; yet it is softer springs that give better ride control. Large tandem caravans with ATM's over 3 tonne will have to use very stiff springs because of the weight. Then, in certain conditions, you may be towing a kangaroo!

Although the solution has to be a lighter caravan or camper trailer, carrying large water loads gives a wide weight range for the coil or leaf springs. And this means they are difficult to tune.

offroad caravan airbag suspensionAir suspension lets you set the ride height and carry a higher load for a softer spring rate.

It helps if your chassis is designed for air suspension.

These are key requirements:

  • Alloy construction for longer life and better securing to independent suspension
  • Internal "bump stop" so that if there is a leak, you can limp home on these
  • graduated shape gives a variable spring rate depending on position of inflation
  • purpose built for off road towable caravans and campers trailers rather than applying a car product (towables can have three times the inertia energy because of the pendulum effect - cars dont have that)
The photo on the right shows a cut-away view inside.
Here is a video of the air suspension running with the three different positions ( each position runs for about 20 secs)
  • Low height position: 40mm over bump stop, pressure at 40psi
     
  • Medium height position: 65mm over bump stop, pressure at 44psi
     
  • High position: 100mm over bump stop, pressure at 47psi
The key learning out of this test is the very small PSI change for a significant height change. This shows a similar spring rate at the different levels.

 

Become well informed and download our Open Reasearch book on suspension design.Suspension design in an offroad caravan

Topics: offroad caravan, off-road caravans, Tyre Pressure Monitoring, off-road camper trailers, air suspension, suspension, air springs, mono-tube shock absorbers

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The Kimberley Blog

The Kimberley Karavan, a lightweight folding off road caravan that can go anywhere. Kimberley Karavans are unique with their internal shower and toilet, comfortable internal seating and luxury finishes.