What Are The Fundamentals Of A Caravan Chassis?

Have you ever wondered what goes into making a caravan chassis? Do you want to understand more about your caravan and what it’s made of? If so, this article has been written for you! Please keep reading as we explain everything you need to know about a caravan chassis.

What Is A Chassis?

The chassis of a caravan is widely described as being the skeletal backbone of your caravan. It is a metal frame that acts as the foundation of the caravan body and is where several parts of the caravan such as the jockey wheel and stabiliser legs are attached to. There are different grades of steel used for chassis. For a typical Aussie caravan, the Dual Grade Rectangular Hollow Section (RHS) is commonly used as longitudinal beams while Square Hollow Section (SHS) steel is used as cross beams. The steel comes in different sizes and thicknesses depending on the design and build of the chassis. A-frames are used to increase the strength and durability of a chassis. They are usually welded onto the longitudinal beams and can be enhanced by an additional sheet of steel which is known as an A-frame reinforcement plate. However, A-frames can be aggravated by weight stresses such as bike racks and rear storage units which can cause issues, so it’s important to be mindful of this possibility. Chassis also have what is known as risers. They are sections of RHS which are installed on top or under the parallel chassis side sections to improve clearance and body height. This allows the caravan to have a flat floor surface and to have enhanced wheel articulation.

How Are Chassis Made?

The design process of a chassis is an intricate and technical engineering process. The beginning of its design process is largely formulated on programs such as Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) programs. There are also more sophisticated techniques such as element analysis which is able to detect stress points and how they can be modified for optimal quality. There are also many types of chassis finishes which can range from painted surfaces to hot-dipped gal. Common examples of coating include DuraGal and SupaGal which can be applied inside and outside the steel surface to prevent rusting. The coatings are usually very thick—around 56 to 80 microns thick—to foster durability. After the steel is coated, it goes through a process known as galvanizing which is done by basically dipping the steel in a variety of chemicals to cleanse it. Once it’s cleansed, it’s dipped again into molten zinc at a high temperature of about 450 degrees Celcius to ensure that every part of the steel is covered. Welding is another vital component in the creation of chassis. The common type of welding in chassis is stitch-welding which uses short runs of intervals of 350 to 450 mm. This allows the chassis to be flexible and to have increased movement when tackling the harsh Australian road conditions.

What Are The Limitations Of A Chassis?

First, it is important to note that a composite body such as the chassis may have a hard time supporting suspension, so you should be mindful of any attachments you may want to add. Moreover, Aussie caravans are generally known to be pretty hefty in weight, though some caravans have applied European chassis designs to alleviate this. They do this by using C-channel steel cross beams as a substitute for SHS steel to reduce weight and maximise strength. To date, there have not been many alternatives for improved weight. This is because it is generally cheaper to stick with the RHS/SHS set up. However, there have been methods to create a stronger van body so that the chassis can be built lighter. Aluminium chassis have become very popular for the reason. They give a nice balance between weight and strength.

How Do I Maintain My Chassis?

Chassis don’t really require too much maintenance but do require a check-up from time to time. If your van is quite old or second-hand, make sure you check for rust in the A-frame. Rust problems include clear signs of corrosion and hollow sounds in the box section. If you and your family like to travel with your caravan regularly to the beach, you need to make sure to rinse your chassis particularly if it was exposed to seawater. This is the perfect breeding ground for rust. Additional measures to take include making sure that the handbrake lever is greased, the tow coupling is cleaned and re-greased for movement, the spring which holds the lock-down clip is in good condition, the A-frame does not have a lot of scrapes and scratches, and the safety chains do not show any signs of deterioration.


So there we have it, a thorough explanation of a caravan chassis. As you can see there is a lot of technical work that goes into assuring that the chassis is not just strong, but also flexible. A good quality steel chassis should last for many years with very little maintenance however, some small checks are required from time to time just to be on the safe side. If you are looking for a reliable, high-quality caravan chassis, then look no further than ARV Chassis & Trailers. Please call us today on (03) 9111 5367 or message us through our contact page if you want the best caravan chassis in the market.