Narhay

I've got a suntour cable housing stop to put on my downtube and a Shimano 600 Arabesque FD replacement for my mangled simplex on the seat tube.

The tubes are 28mm in diameter, the clamps on these are 28.6mm. The cable stop might be OK as it is flexible steel and has a bit of a gap but the FD certainly slides up and down.

It is a relatively nice bike - PX10. What solutions have you guys come up with? I could always find another french FD but I have this 600 replacement already. I was thinking of a single layer strip of black newbaums cloth bar tape under the clamps but I'm not sure it would be thick enough. I also don't have any spare at this moment to test.

big chainring 

A piece of old inner tube. If you want to get fancy you can glue the tube to the inside surface of the derailleur clamp, let dry, and trim with a razor knife.

Narhay

...pretty smart and doesn't cost me anything.

verktyg 

The glued on rubber shim is an interesting idea. My concern is that the rubber shim might compress enough in use to break down and let the components move.

Back in the 70's when we mounted Shimano front derailleurs on French bikes, we filed down the clamp and the body in the areas marked below. It's a time consuming job but when done correctly the derailleur stays put.




verktyg

Chas.

rootboy 

I found I had no trouble mounting a Nuovo Record front derailleur on my French bike by coating the inside of the clamp with a couple of thin coats of clear Plasti-Dip.
It helps to protect the paint too. You just have to let the stuff dry, very thoroughly, before using it.

headset

This has work for me as well.

rootboy 

I tried E6000 once too, or whatever it's called. Silicone adhesive. Not as good. Too soft. What I like about PlastiDip is that it dries harder than these, but still with just a bit of flexibility, to act as a cushion. My concern when I first tried it was that it might affect the paint. But so far so good. But I made sure it was good and dry so there were no remnant off-gases, etc. I let my parts sit for 3 days as I remember.

big chainring 

"Just a pinch between your cheek and gum."

bikemig 

This is a 4 year old thread but it has useful info for fitting a 28.6 front derailleur onto a French bike with metric sized tubing.

There is a post on Sheldon Brown's website from a contributor about French bikes. I disagree with much of what the post says but the poster does talk about some of the problems in shimming a front derailleur to fit.

https://www.sheldonbrown.com/kunich.html

bikemig 

This is a cool solution,

Bill in VA

Arise Zombie Thread!

This!!! plus (and/or) a shim made from an aluminum beer or soda can. Adding a single layer of stretchable electrician's tape to one side of the can shim (usually the seat tube paint side) anchors it. Careful cutting of the can with an X-acto or scissors will make is invisible under the clamp. Also works well with triples that often cause more twisting.

tiger1964 

So this is "a thing"? Noticed on my Gitane that the Velo Orange water bottle cage I installed on the down tube looks good, but the straps' bolts are cinched down 100% and still slipped a bit. Time to shim!

verktyg 

French, most Spanish, some Belgian and a few other countries used metric diameter tubing with 28mm seat and down tubes vs. 1 1/8" (28.575mm) on British, Italian, Dutch bikes and so on.

Simplex and Huret made FD and shift lever clamps in both diameters - rarely if ever marked.... Cause for many broken Huret Jubilee FD clamps.

The Italian and Japanese component makers used inch size 1 1/8" (28.575mm) clamps almost exclusively. BTW, paint on the tubes can add up to .5mm to the diameter.

Back in the 70's before bikes came with braze on H2O bottle cage mounts, we used to wrap a layer of cloth handlebar tape on down tubes under the cage clamps. Protected the paint and reduced the chance of rust.

verktyg