Classy chassis and excellent axles

IN SIMPLE TERMS, caravans are big white boxes built on a rolling steel chassis, consisting of a steel frame and axle(s).

This very practical design has been around for some 100 years and is a very straightforward, cost-effective solution to the conundrum of creating towable accommodation.

Over the years, chassis design has evolved to maximise safety, towing manners and longevity, and to reduce weight.

The chassis is a steel frame, stretching the length and width of the caravan, onto which the living accommodation is bolted and (sometimes) bonded.

At the front end of the chassis is the hitch head, the A-shaped frame housing the handbrake, breakaway cable, jockey wheel and towball, and connecting the caravan to the car.

Modern caravan chassis are galvanized to prevent or at least minimise corrosion. This involves the steel members being coated with a layer of corrosion-resistant zinc. For caravans, a ‘hot-dipped’ process is employed, whereby the metal chassis members pass through a bath of molten zinc, heated to around 460°C. Once coated, the zinc reacts with oxygen in the air to form zinc oxide.

This reacts again with carbon dioxide