Author Topic: Slipping rear mudguard rubbing on tyre  (Read 405 times)

Slipping rear mudguard rubbing on tyre
« on: February 10, 2019, 03:49:41 pm »
Ok, so I’ve shoe-horned 28mm tyres in when max specified by the manufacturer is 25mm, therefore clearances are minimal, but given I only ride on road, and my usual routes are pretty clean, this hasn’t been a problem. What has is getting the ‘guard to stay put, it slips through the crimped saddle piece at the seatstay brake bridge, so the section between there anD the brace behind the BB flattens out and rubs. Suggestions to stop this happening would be welcome  :).  I guess I could cut a small rebate either side of the guard at the saddle position so it can’t slip.
We are making a New World (Paul Nash, 1918)

Re: Slipping rear mudguard rubbing on tyre
« Reply #1 on: February 10, 2019, 05:57:27 pm »
Drill four holes two along each edge of the guard about 10 mm apart. Thread a couple of cable ties through and over the brake bridge. Good for front, over fork crown as brake bolt L clamp takes out clearance underneath in centre. Use small bits of inner tube under ties  to avoid chafing tape
Don't notch the guard edge. It will crack
BTW is it a small/compact frame?

Re: Slipping rear mudguard rubbing on tyre
« Reply #2 on: February 10, 2019, 06:09:49 pm »
do you not just need a better crimp?

FWIW there are several things that may be helping the mudguard move

-  not enough stays; you need a vertical stay on most rear mudguards; (a single set of stays somewhere near the back isn't good enough)

- wrong curve in the mudguard; i.e. the mudguard is strained somehow when it is fitted to the frame

- too much weight at the rear of the mudguard. IME anything more than a very lightweight reflector is liable to help the mudguard move.

if any/all of the above are bad enough, it won't matter how you fix the mudguard, it'll probably break.

 FWIW an LBS mechanic once showed me a good dodge for better crimping (which will counteract moderate sliding tendencies); he took an old (and fairly blunt) set of large side cutters and nipped the folds in the bridge brace, in such a way as the freshly deformed region only just caught the edge of the mudguard. The resultant deformation not only grips the mudguard better, it also means that the ears on the brace resist being unfolded rather better than they would otherwise.

cheers

Re: Slipping rear mudguard rubbing on tyre
« Reply #3 on: February 10, 2019, 09:13:35 pm »
Thanks guys. Not a compact frame, a 56 Genesis. The blunt side cutters sound good.
We are making a New World (Paul Nash, 1918)

Re: Slipping rear mudguard rubbing on tyre
« Reply #4 on: February 10, 2019, 10:17:40 pm »
I'd just go with the cable tie option as Aidan suggested. I always do that when fitting mudguards.

zigzag

  • unfuckwithable
Re: Slipping rear mudguard rubbing on tyre
« Reply #5 on: February 11, 2019, 02:00:38 pm »
a drop or two of glue between the mudguard and a bracket?