narrow chainstay bridge rear fender mounting tips
 

i have a new pair of berthoud fenders and need to mount them on my Raleigh Super Course. the front goes on perfect. the rear needs some doctoring. i've come into 2 issues. the chainstay is narrower than the fender by 3mm and there is no chainstay bridge hole for mounting. i've learned well to head the advice of BF members before doing any sort of hacking. :) so here we go...

for the first problem i thought i could trim the edges a bit with tin snips so i get a nice fit. even though i'd prefer not to modify the fenders in this way, i've read that the fender should drop a bit below the bridge to get the best foot protection. perhaps just squeezing the fender a bit would work?

for the second problem I thought i could use a P-Clamp, which would move the mounting point 15mm lower thus raising the back.

a solution which i find a lot of people recommending is using zip ties. i'm not against it but the only real problem here is that the SC's wheelbase is pretty long. to get a nice fender fit, i have to distance the fender a bit from the bridge. like peter white does here:

http://www.peterwhitecycles.com/imag...bertffspac.jpg

i feel like the zip tie would only work if the fender was close the bridge.

ps i also considered drilling a hole in the bridge, but that could get ugly especially seeing that i already painted the frame and don't own a thread cutter.

as always, any and all suggestions (and pictures) are welcome!

cheers,

this is also a nice solution!

http://1.bp.blogspot.com/_C1XrRVl3W8...ring+thing.jpg

I'd go the P-clamp rout maybe with some sort of spacer. I've heard that cutting/snipping fenders causes weak spots for cracks to start, so pinching (albiet more frustrating) might be the way to go...I have a project in the workd that will be having the same issues :notamused:

Good luck,
Chris

I think fenders will crack no matter what, if given enough time. My vote is don't worry about it, trim off a few mm on each side of the fender so it slips in.

As far as mounting, a P-clamp does sound like the best idea, don't break out a drill unless you absolutely need to. I think a long bolt, with a couple of spacers, either washers, or presta nuts, or whatever you have lying around should do the trick.

Zip ties would work, but they look rather inelegant, and give you a kind of wonky fender line. Both are just aesthetics though, they work just fine.

Fenders like the SKS chromplastics will not crack. You can modify them at will. Also the fender does not have to attach to the bridge mount. You can also punch two holes and ziptie them to the chainstays.

Don't cut the fender. Bend it. You can crimp it neatly so that it looks like it was made that way.

yeah i am more and more against cutting, since it is irreversible and could scratch the paint badly.

by crimp you mean dimple it where it would meet the chainstays? any good tips on how i can do that?

can you show me a pic of the result?

I can't take pictures because my memory card got corrupted.

Here's the tool I used:

http://www.irwin.com/irwin/consumer/...6&search=false

This is the best I can do for a picture of the fender until I can get a new card. I measured the distance between the stays at the point where I wanted the fender to sit and marked the fender with a sharpie. I used the tool to flatten the fender to either side of the marks and then bend it to the angle of the stays. I did this to the bottom 3/4" of the fender. A stainless screw and Nylok nut through the chainstay bridge wedge the fender between the stays so it won't rattle.

http://inlinethumb58.webshots.com/31...600x600Q85.jpg

Aren't those metal fenders, Dirtdrop? Plastic fenders won't take a permanent bend quite so easily.

On the last two bikes I've added fenders to I've used spacers like those shown in the first pic. I didn't need it for chainstay clearance on the first bike, but on my most recent build I did.

Who besides you and operator is talking about plastic fenders?

I forgot to mention that I used duct tape on the jaws of the pliers to prevent scratching.

I use carbon fiber tubing for spacers. (broken kite rods)

I got thrown off by Operator's reply. A quick Google of Berthoud fenders set me straight.

oh.

hey dirtdrop.

that's a great picture btw.

thanks for the info. i'm having a hard time understanding how that tool was used. the clamp looks almost as wide as the fender. you just grabbed and bent the fender edges, right? i imagine you clamp the tool perpendicular to the bottom of the fender and bend in?

i thought of laying the fender on a thinner wheel or rounded object and tapping (hammering) a small pipe against the feder edges, at the chainstay points, to crimp/dimple them.

i'd rather not buy a tool for this purpose - especially seeing that i already have to return the tin snips :) ,