Weight distribution hitches: what they do, and what they don't

A weight distribution hitch moves some tow ball load forward to your front axle. It doesn't reduce mass or fix an overload. When to use one, and when not to.

Facts checked 25 Sep 2026

What a weight distribution hitch is

A weight distribution hitch (WDH) is a set of spring bars that connects the trailer's A-frame to a special hitch head on the tow vehicle. You will also see it called a load distribution hitch, a load equaliser or a weight distribution system.

When a heavy caravan is hitched, its tow ball load pushes down behind the tow vehicle's rear axle. The rear suspension drops and the front rises. That can reduce steering and front brake performance, and throw the headlights out of line. See front and rear axle limits.

A WDH puts tension on the spring bars to lever against that. In effect it levers the car against the caravan, forcing the front end back down.

What it does

Each of these undoes part of the sag described above.

It moves load forward. A WDH transfers some of the load on the tow ball to the tow vehicle's front and rear suspension. Some of the load also goes back onto the trailer's own axles.
It levels the rig. It helps level the drawbar, and brings the tow vehicle's attitude back as near to level as possible.
It can restore steering and braking feel, by putting weight back on the front wheels. That helps maintain ride height and steering control.

What it doesn't do

This is the part that matters most for load.

It doesn't reduce mass. The vehicle and caravan weigh exactly what they did before. Moving load, as above, only changes where that mass sits. Your total on a weighbridge, and against GCM, is the same.
It doesn't fix an overloaded rig. The WA Department of Transport says a WDH must not be used to correct excessive tow ball download, or to correct an overloaded rear axle. Queensland says never use one to make up for a badly loaded trailer. These devices are not designed to make up for excessive loads or poor loading.
It doesn't raise any rating. Your GVM, GCM, tow ball rating and axle limits don't change because a hitch is fitted.

If the rig is over a limit, the fix is to change the load, not add a device. Aim for a relatively flat vehicle and trailer without load levelling devices first. RAC WA's view is that a lighter, smaller caravan is far better than relying on a hitch to level the ride. See loading your caravan.

When manufacturers require or prohibit them

Even where a WDH is the right tool, it is not always allowed. This varies by vehicle, and it matters.

Some vehicle manufacturers require a load distribution device as part of their towing package for heavier trailers, and others advise against using one.
Using one with a vehicle or towbar not designed for it can damage the vehicle, the towbar or both.
WA says a WDH must not be used where the vehicle, caravan, towbar or hitch manufacturer advises against it.
A WDH may overload the towbar and its components. Use heavy duty towbars and attachments with one, and get advice from the towbar manufacturer or caravan dealer first.

So before fitting one, check the towing section of your owner's manual for your exact variant, and the towbar's own instructions. If either says no, the answer is no.

Sway control is a different job

A weight distribution hitch spreads load. Sway control resists the trailer swinging side to side. They are separate jobs, though some hitch systems combine both.

Sway control devices fit between the vehicle and trailer. Follow the device manufacturer's instructions and ratings.
Electronic trailer sway control is a feature of some tow vehicles. Transport for NSW recommends using a tow vehicle that has it.
Brake controllers can help too. An electric brake controller can apply the trailer's brakes on their own to help control sway. If a trailer does start to sway, the vehicle's brakes are a last resort and the trailer's, applied gently, come first; trailer brakes sets out the full response.

None of these replaces good loading, any more than a WDH does. Too little tow ball load makes a trailer more prone to sway (see tow ball mass).

Setting one up

Follow the hitch manufacturer's instructions, and the vehicle manufacturer's if it gives any. The general points are:

Load the rig properly first. As above, get the vehicle and caravan sitting as level as you can without the hitch.
Match the hitch to your tow ball load. A hitch rated too low won't level the rig enough. One rated far above your needs will transfer too much load to the vehicle.
Check the front of the vehicle, the end the hitch is there to bring back down. Measure the front wheel arch height with and without the caravan. If it is the same, or slightly lower, the car is well balanced. If it is noticeably higher with the caravan hitched, something needs to change.
Mind off-road couplings. High-articulation couplings used with a WDH are for highway driving only, not for articulated off-road driving.

Then weigh the rig as you will travel, hitched with the bars tensioned. See how to weigh your rig. A hitch that looks right can still leave an axle over its limit.

Common questions

Does a weight distribution hitch reduce tow ball weight?

No. The trailer's tow ball mass, as you would measure it without the hitch, is set by how the trailer is loaded. The hitch changes how the rig carries that load, moving some of it forward to the vehicle's front axle and away from the rear. As covered above, it doesn't make anything lighter, and it doesn't change the tow ball rating you have to stay within.

Can a weight distribution hitch fix an overloaded rear axle?

No. As above, the WA Department of Transport says a WDH must not be used to correct a rear axle overload or excessive tow ball download. Reduce or move the load instead.

Can I use a weight distribution hitch on any vehicle?

No. Some manufacturers require one for heavier trailers and others advise against them. Check your owner's manual and the towbar's instructions first.

Is a weight distribution hitch the same as sway control?

No. A WDH spreads load. Sway control resists the trailer swinging from side to side. Some products do both, but they are different jobs, as set out above.

Sources

Authorities

Motoring associations (advice)