Should I grease my tow ball?

by | Sep 22, 2020 | Articles, Caravan/Tow Vehicle Behaviour & Suspension, General, Roll

 

Should I grease my tow ball?

Tow ball friction plays a vital role in reducing caravan sway

Should I grease my tow ball is a question asked by caravan owners worldwide. A recent poll in Australia showed that slightly over half do so, but primarily to reduce wear.

Tow ball friction plays a vital role in reducing caravan sway. Those owners who grease them unwittingly prejudice safety for the possible need to renew the tow ball every ten or so years. In practice a non-greased tow ball has negligible wear. Even it were to need replacing, the cost to do so is a mere A$15-25.

The common advice to use grease for trailer hitch ball is misplaced. RV Books advises that you do NOT grease that tow ball – nor use any liquid or powder that may reduce that vitally needed friction.  While tow ball friction is only one factor it’s one of a range of issues that factor into how to stop caravan sway.  

Adding tow ball friction

The world-wide AL-KO company produce a tow ball that has four friction linings forced against the tow ball from both sides plus the front and rear. In technical terms, they exert the equivalent clamping torque of 320 Newton/metres force. In Australian terms, this is ‘b-y tight!’. Swaying or pitching movements are effectively suppressed before they become serious.

ALKO hitch is designed to manage tow ball friction

The AL-KO friction tow ball hitch.

Friction anti-sway limitations

Any hitch (or add-on friction sway control) has a fundamental limitation. This is that unless deliberately increased, frictional force remains constant. The vectored sway forces that they dampen, however, increase with the square of the road speed. Any form of friction hitch or friction stabiliser is thus only marginally effective at (say) 100 km/h (about 62 mph). This was actually confirmed (following extensive controlled testing) in a technical paper some years ago.

That any given frictional force remains a constant is why most UK/EU caravans use the friction hitch (for low/medium speed) comfort. They rely on electronic stability systems (that brake the trailer’s wheels) at high speed. Even here, the makers are cautious. They advise that while usually effective, these systems cannot overcome the more basic laws of physics. Ignore all advice to lubricate, or any friction-reducing manner a trailer tow hitch.

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.

Cover of Caravan and Motorhome Books by Collyn Rivers

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 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

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

Why Caravans Roll Over
and how to prevent it

Explains in detail every aspect of tow vehicle and caravan 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, caravans, 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

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.

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, caravans, 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 caravan 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