Should I grease my tow-ball?
Tow-ball friction plays a vital role in reducing caravan sway
Should I grease my tow-ball is asked by caravan owners worldwide. A recent poll in Australia’s Caravanners Forum.com 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.
So do NOT grease that tow-ball – nor use any liquid or powder that may reduce that vitally needed friction.
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.
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.
Collyn Rivers (brief bio)
Collyn Rivers is an automobile research engineer with a lifetime in the motor and writing/publishing industry. He spent a brief time with de-Havilland, before working at the Vauxhall/Bedford Motors Research Test Centre in the UK. Collyn moved to Australia in 1963, initially designed and building scientific and engineering measuring equipment.
In 1971, Collyn Rivers founded what, by 1976, became the world’s largest-circulation electronics publication, Electronics Today International. From 1982 to 1990, he was technology editor of The Bulletin and also Australian Business magazines. In 1999 Collyn Rivers started two companies: RV Books and Solar Books.
RV Books and Solar Books current books are the top-selling Why Travel Trailers Roll Over – and how to prevent it, the all-new How to Choose and buy an RV, the Caravan & Motorhome Electrics, the Camper Trailer Book, Solar That Really Works and the soon to be launched American Travel Trailer Book. Also, Solar Success (this also for homes and properties).
Collyn is a regular contributor to major associated websites in America and Australia (and uses that name).