Towing Without a WDH – Weight Distributing Hitch 

by | Jul 17, 2020 | Articles, Caravan/Tow Vehicle Behaviour & Suspension, CMB, Health & Safety, Roll

by Collyn Rivers

Towing Without a WDH

Towing without a WDH (weight distributing hitch) is often feasible. A WDH is not needed if a tow vehicle’s laden weight is equal to or exceeds that of the laden travel trailer. Nor is a WDH needed for any trailer under 4 metres. A WDH may even cause instability.

Many RVers ask about towing without a WDH

A WDH attempts to compensate for issues better avoided. One is towing a laden travel trailer that exceeds the laden weight of whatever tows it. It is, for example, common to see 2500 kg (laden) dual-cab utes towing 3500 kg (7715 lb) travel trailers. Another is towing a travel trailer longer than six or so metres.

For on-road stability, a conventional travel trailer needs to be nose-heavy by 8-10% of its laden weight. When hitched to its tow vehicle that (typically 200-350 kg [440-770 lb]) pushes down the rear of that vehicle. In doing so, that levers up the front of the tow vehicle. This reduces the weight on the tow vehicle’s front tyres.

Where, however, that tow ball weight is comfortably within the laden tow vehicle’s payload, that front tyre weight reduction is too small to be an issue. It is, however, necessary to increase tow vehicle rear tyre pressure by 50-70 kPa (7-10 psi).

Some travel trailer owners fit a WDH because a sales-person advised it. Or by following misleading advise on Australian RVers forums. Fitting a WDH when not needed, can introduce unwanted issues. Towing without a WDH is preferred unless really needed.

Weight distributing hitch.

Weight distribuing hitch. Pic. Jayco.

How a Weight Distributing Hitch works – and its unwanted effects

A Weight Distributing Hitch is, in effect, a springy light beam. By levering up the rear of the tow vehicle, it restores weight (down-force) from the tow vehicle’s rear tyres to its front tyres. While a good and useful concept, a WDH only counteracts tow ball downforce. By reducing tow vehicle rear tyre loading, those tyres become less able to counteract the yawing travel trailer‘s side forces on the rear of the tow vehicle.

The overall effect of a WDH is thus to reduce the rig’s ‘cornering power’. It does so by an appreciable amount. The USA’s J2807 Standard notes that ‘cornering power’ is reduced by 25%. Furthermore, those strong side-forces on the tow vehicle’s rear tyres may even cause those tyres to steer the tow vehicle. If that happens a jack-knife is virtually inevitable.

The above does not imply that the rig inevitably misbehaves at speed – but it is more likely to if ‘hit’ by a strong enough side force – such as wind gust. Or by cornering too fast. There is, however, a correlation between tow ball mass and safe speed. The lower that mass, the lower the safe speed. There is a very strong argument for that traditional 10%-12%. In the USA it is often 14%.

Towing Without a WDH – Summary

Fitting a WDH to a rig that does not need one is not only pointless. It introduces issues that do not exist without one. Towing without a WDH is feasible if the laden travel trailer weighs the same or less than the laden tow vehicle. Towing without a WDH is also feasible for correctly laden travel trailers less than six or so metres (about 20 feet).

If the weight issue is only minor, towing without a WDH is feasible by carrying the travel trailer’s spare wheel in the tow vehicle.

A full explanation of Towing Without a Weight Distributing Hitch (WDH) is feasible is in our book Why Caravans Roll Over – and how to prevent it.

Collyn Rivers is a semi-retired automobile research engineer.  He is the author of seven books, five of which are about making RVs and solar work optimally.

Caravan and Motorhome Electrics

The essential handbook for anyone with an RV of any kind.  Everything you need to know to make the electrics in your rig work for you.

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Why Caravans Roll Over
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Explains in detail every aspect of tow vehicle and travel trailer stability. This is what you need to know to be safe on or off the road.

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of Why Caravans Roll Over.  Just ask.
ISBN: 978-0-6483190-6-1

Solar That Really Works!

Solar that Really Works! covers the design, installation and use of solar in cabins, camper trailers, travel trailers, fifth wheelers, campervans and motor homes.

eBook versions

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The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of Solar That Really Works!  Just ask.
ISBN: 978-0-6483190-3-0

The Caravan & Motorhome Book

The Caravan & Motorhome Book covers every conceivable aspect of campervan and motorhome usage. If you own a camper van or motor home, you'll want this book.

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of The Caravan & Motorhome Book. Just ask.
ISBN: 978-0-6483190-5-4.

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Caravan and Motorhome Electrics

The essential handbook for anyone with an RV of any kind.  Everything you need to know to make the electrics in your rig work for you.

Cover of Caravan and Motorhome Books by Collyn Rivers

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of Caravan & Motorhome Electrics.  Just ask.
ISBN: 978-0-6483190-8-5

Solar Success

Whether you’re building a new home or adding solar to an existing structure, this is the one book you can’t afford to be without.

eBook versions

Paperback version

Any bookshop, whether online or bricks and mortar, can order copies of Solar Success.  Just ask.
ISBN: 978-0-6487945-4-7

The Caravan & Motorhome Book

The Caravan & Motorhome Book covers every conceivable aspect of campervan and motorhome usage. If you own a camper van or motor home, you'll want this book.

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of The Caravan & Motorhome Book. Just ask.
ISBN: 978-0-6483190-5-4.

Solar That Really Works!

Solar that Really Works! covers the design, installation and use of solar in cabins, camper trailers, travel trailers, fifth wheelers, campervans and motor homes.

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of Solar That Really Works!  Just ask.
ISBN: 978-0-6483190-3-0

Why Caravans Roll Over
and how to prevent it

Explains in detail every aspect of tow vehicle and travel trailer stability. This is what you need to know to be safe on or off the road.

eBook versions

Paperback version

The book retailers set their own prices which can vary substantially. We'll aim to keep a selection of the better prices above.

Any bookshop, whether online or bricks and mortar, can order copies of Why Caravans Roll Over.  Just ask.
ISBN: 978-0-6483190-6-1