Glossary of terms.

• Slide – the sliding wall of a fifth wheel (see “What are slides? How do they work?”)

• Fifth Wheel hitch – the turntable type coupling installed in the trays of utes and pickups

• Fifth Wheel – a caravan that has a raised front section or “goose neck” that is towed by a pickup or ute

• Pin – Fifth Wheels use a 2 inch pin (rather than a 50mm ball coupling of a traditional caravan) as their main coupling connecting it to a towing vehicle

• Pin Box – The pin (see above) is typically connected to a fifth wheel by a pin box. The pin box will typically have adjustments to allow the pin to be raised or lowered. This in conjunction with adjustment on the fifth wheel hitch allows the fifth wheel to be connected to various height tow vehicles The pin box can be of a standard type which has the pin located generally in line with the front of the fifth wheel or it can be an extended pin box (see below).

• Extended pin box – Fifth wheel hitches are normally installed to positioned the pin as close as possible to the rear axle of the tow vehicle. This in many cases is too close to the rear of the cabin of the tow vehicle to allow the fifth wheel to turn properly. The extended pin box typically extends the pin 13 inches forward of the fifth wheel and as a result moves the fifth wheel further back from the cabin. Sometimes this is still not enough to allow really tight turns such as manoeuvring into difficult caravan parks sites. In this case a sliding hitch is used, (see below)

• Sliding Fifth Wheel Hitch – When a tow vehicle has very limited distance between the rear axle and the back of the cabin (see above) a sliding hitch is often used. This is quite common on dual cabin utes and pickups. Under normal travelling conditions the hitch is in the forward position with the pin as close as possible to the rear axle. When tighter turns are required the hitch is moved back into the manoeuvring position thus moving the fifth wheel further back from the cabin allowing it to turn more sharply. Please note that fifth wheels should not be towed at speed with the hitch in the back position. Firstly the hitches were not designed to handle the loads of high speed travel in the back position and secondly it can cause the fifth wheel to sway and redistribute weight off the front wheels of the tow vehicle..

• ATM – Aggregate Trailer Mass – the total weight of the trailer loaded to its legal limit

• GTM - Gross Trailer Mass - (towed weight) the total weight on the wheels of a trailer that can still be legally towed,

• Tare weight – the weight of the fifth wheel dry and unladen

• GCM – Gross Combined Mass – the total allowed weight of the towed vehicle plus the fifth wheel with both laden.

• Travel Trailers – what the US call caravans

• Umbilical cord or pig tails – the main (12 volt) electrical cable between the tow vehicle and the fifth wheel

• Safety or breakaway brake – unlike caravans that have safety chains a fifth wheel has a thin plastic coated steel cable which you attached to the handle of the hitch when the fifth wheel is hitched to the tow vehicle. If the fifth wheel separates from the tow vehicle the cable trips the fifth wheel’s brakes.