Most caravans impose a significant weight on to the tow bar of the towing vehicle. This in effect makes the rear of the vehicle sag down, and the front of the vehicle lift up. In turn, this causes a vast reduction in vehicle handling and performance as there is less weight on the steering tyres of the vehicle. This can be extremely unsafe, especially in emergency situations.
A common solution to this problem is the use of a caravan weight distribution hitch (WDH). These are the long metals bars you see on each side of the coupling – extending down the A-frame of the caravan. These metal bars are like spring levers which assist to lift the rear of the vehicle to get it level again.
Caravan weight distribution hitches have 3 main components:
- Equaliser bars – the two bars that run along the A-frame and connect to the vehicle.
- Mounting plate – horizontal steel plate which the tow ball screws into, and the equalizer bars connect to – some also have a connection point for an anti-sway bar.
- Shank – the adaptor that slides into your vehicle's tow bar receiver (the 2"/50mm square hollow tube). The shank is normally "L" or "T" shaped and has a vertical section to which the mounting plate connects to. The vertical section has multiple holes in it which allows the mounting plate to be moved up/down so your rig will be travelling level at all times.
Common brands of caravan weight distribution hitches are Hayman Reese Weight Distribution Hitches and EAZ Weight Distribution Hitches. Both a good quality units, but have some different features.
The Hayman Reese Weight Distribution Hitches come with the "shank", but you need to purchase them separately with the EAZ kits – which does give you a bit more flexibility if you need a different length shank. Both brands have similar weight ratings – with basically a light (600lbs / 135-275kg) and heavy duty (800lbs / 275-365kg) option. Hayman Reese kits have two styles – "Classic" and "Standard". The difference is in the shape of the equaliser bars – the "Classic" series suits draw bars up to 4" in height, with the "Standard" model suiting draw bars from 4-6" in height (they loop down further so they don't intefere when turning).
The Hayman Reese units also feature an optionals way controller – the Friction Sway Control, and the Dual Cam HP Sway Control.