WD Motorcycle forum

Author

Comment

Sep 5, 2021 - 6:19PM

Re: Wheel security bolt

Danny Burt

Thanks guys,

Rob,

If you do come across the right one for a M20 that would be brill. Very kind of you indeed!

As mentioned, not going to use it so condition is not a issue.

Thanks

Danny

Hi Danny
Sorry no luck at Beaulieu.
Rob

email (option): robmiller11(a)yahoo.co.uk

keith chandler

Aug 29, 2021 - 8:31PM

Re: Wheel security bolt

Rob Miller

I knew I had one somewhere, red coloured rubber is probably correct for WW2, its marked

D.R.Co Ltd - Dunlop Rubber Company?

W.D. - War Department?

W.M.2 - rim width, correct for a Norton 16H but not a BSA M20 which used W.M.3 rims, I wonder if that's why BSAs weren't urgently given them at the same time as the other makes, the same 3.25 19 tyres being used on both widths of rim?

Rob

I have a couple somewhere in the garage which I think came off a SWD Big 4 and the rubber element of the security bolt had been replaced with Khaki coloured canvas. All to do I guess with saving the use of rubber.

email (option): keithchandler@clistandchandler.co.uk

trevor

Aug 30, 2021 - 8:37AM

Re: Wheel security bolt

Ian Wright

['The security bolt goes through the rim to prevent the tyre slipping into the rim well when the tube deflates...']

I always believed tyre clamps were fitted to prevent the tyre turning on the rim and pulling the valve from the tube when running low pressures for increased off road grip....Thus their continued use on trials machines and generally, not road bikes these days...Ian

Not sue if we are talking about the same item.
I bought some modern security bolts to replace the ones in the B40
The B 40 ones clamped onto the actual case ( sort of ) pinching it between the rim & the sides of the bolt as made evident by rust & fretting on the inside of the tyre.
The new one s were way too narrow to touch the sides of the tyre but would stop it sliding off the lip & falling into the rim well .
Like others have mentioned, I fitted some bolts & ground the head smooth .
Without them the wheel was very hard to balance.

When I first got the WM20 I had no idea about correct tyre pressure for girder forked bikes so I used the recommened tyre pressures.
It was fitted with a ribbed front & K81 rear with security bolts.
Well I can confirm that the bolts do not stop the tyre rotating on the rib and ripping the valve out.
And I have the boots with holes in the soles from pushing the bike for very long distances to prove it .
Eventually I found with that combo anything under 20 PSI would cause the tyre to rotate probably made worse by my riding technique of heavy engine braking with light brake applications.

Ian Wright

Aug 30, 2021 - 10:13AM

Re: Wheel security bolt

A You Tube search resulted in an explanation... 'How the rim locks work on your dirt bike/Fix your dirtbike.com'...
However, I'd like to find some Dunlop info. or something by another manufacturer to confirm...Ian

email (option): ian@wright52.plus.com

Michael Steinmann

Aug 30, 2021 - 2:47PM

Re: Wheel security bolt

I made a fake one from a stainless bolt.
Looks great.

email (option): michasteinmann@gmail.com