Tow Bar Bolt Torque Settings

[ScubaBongo]

Hi Guys,

I've bought a cycle carrier, the type that requires you undo the two big bolts on your Tow Bar, insert a mounting plate for the cycle carrier, then re-assemble to the tow ball.

Before I start - when I come to retighten the two big bolts, what torque value should they be set to?

As I sometimes tow a 1600kg boat &trailer, I don't want to get this wrong!

Cheers

SB

[munroman]

From another forum:

The correct torque for the bolts for the tow ball is 218 Nm. The bolts should be "High Tensile" (i.e. '8.8' Grade or higher), and external serrated washers should be used under the bolt head and nut. As there will be some 'settling' of the bolts/nuts after first use, it would be good practice to re-cheque the torque after some 50 miles or so of towing. Recommended torque settings can be found at
http://www.mechanica...o.uk/torque.htm

Nothing worse than having a ball drop off! :

[ScubaBongo]

From another forum:

The correct torque for the bolts for the tow ball is 218 Nm. The bolts should be "High Tensile" (i.e. '8.8' Grade or higher), and external serrated washers should be used under the bolt head and nut. As there will be some 'settling' of the bolts/nuts after first use, it would be good practice to re-cheque the torque after some 50 miles or so of towing. Recommended torque settings can be found at
http://www.mechanica...o.uk/torque.htm

Nothing worse than having a ball drop off! :

you star, thanks!

[peanutcrusher]

funny that I just did mine up really really tight having said that this info is handy.

[thedogsbollox]

I think it is the same as my old mini's wheel hub nut. When i asked the bloke who restores them what the torque setting was, he answered, "It is FT!" I will give you a clue, the second word is TIGHT. He told me to get the biggest bar i had and put a pipe on the end of that.

[ScubaBongo]

An ovetightened bolt is prone to failure.

An overtightened bolt on a vehicle travelling at 70mph

..... I know someone it happened to.

[dandywarhol]

Don't understand why a shakeproof washer is required under the bolt head - it's the nut which could come off...................

[phedders]

Don't understand why a shakeproof washer is required under the bolt head - it's the nut which could come off...................

A shakeproof washer under the nut will stop the nut turning... but it wont stop the bolt turning in the nut - and hence the washer under the head too.

[dandywarhol]

Fair 'nuf - I've fitted many towbar/towballs over the years and never fitted a shakeproof under the bolt head - never had a towball come loose either come to think...............

The manufacturers only supply 1 shakeproof washer per bolt/nut.
http://www.towsure.com/category/7189-M1 ... ball_Bolts
Once the bolt has stretched through torquing it down, the bolt head is under tension and there's a unidirectional shakeproof washer (designed to slip in a clockwise direction and grip into the nut metal and adjacent metal bracket in an anticlock direction) under the nut, there's no need for another shakeproof washer under the bolt head IMO - It WON'T come undone.