From last week’s post we now want to share about the chassis and suspension of a caravan and fifth wheeler and how they complement each other.
Chassis designs have not changed much over the years.
The main change has been to utilize lighter materials and manufacturing techniques to keep the weight to a bare minimum, yet upholding maximum strength and durability.
Some manufacturers have gone too far with this process and have had major failures with fatigue, cracks and bending. A cracked chassis is an unsafe chassis.
There is a grey area on what is considered an ‘off road’ caravan, and how capable that caravan performs before there are problems.
You may have seen how some manufacturers have tackled this. They normally ‘double-up’ on the main rails of the chassis, and in reality you are doubling up on weight and costs as well.
In our previous post we talked about body construction. The body plays a major part in how the chassis is designed.
Because of the tensile strength in the composite panels, the body practically supports itself. Therefore, the body needs less support from the chassis.
The chassis has been designed to give strength and support exactly where it is needed. We are able to drop the weight down and concentrate on the important fixtures that need the support, like the hitch, tanks and suspension.
A chassis should be individually designed for the body of the caravan and its floor plan. The chassis is then fabricated using super-gal RHS steel framework and re-enforced sheet metal, making it super strong and sturdy. A laser leveling system to ensure all is square, level and at minimum tolerances is a practice undertaken by only the serious caravan manufacturer.
In comparison to chassis design, suspension design has changed over the years.
There is now a larger variety of different types of suspensions on the market. Manufacturers and customers are seeing the benefits in their freedom of choice.
The biggest change has been the addition of independent trailing arm suspension with air springs. The use of Air Springs has been standard in the truck and bus industry for several years as a way of protecting passengers, loads and even the road surface.
This type of suspension has many advantages over traditional coil, torsion or leaf springs. Air suspension allows a soft spring rate with the ability to maintain constant ride height. The independent arms mean that bumps experienced on one side of the van are not directly transferred to the opposite side. As the wheels ride over undulations they stay perpendicular to the road surface.
Another benefit is the ability to level the van across slopes when parked. The Air Springs themselves are able to be adjusted by the flick of a switch to keep constant ride height no matter what load is being carried. In doing so the internal air pressure changes and so does the spring rate giving a perfect ride for all load conditions. The onboard Air Pump and Tank provides a ready supply of compressed air for pumping up tires etc. Literally riding on air, this suspension provides the best protection for your caravan.
About the Author : John Beattie