Bicycle Mechanics - Front derailleur clamp slipping...

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b16a2nr
04-14-11, 11:40 PM
I'm building a new carbon frame and have everything working great, except for the front Sram Red derailleur. The clamp keeps slipping! I've tried Pace carbon non-slip grease, I've tried a sterille clean clamp and seat tube. I've tried slightly over torquing the clamp to 50inch/lbs. Each method still leads to my clamp slipping down a few mm after some shifting, making it impossible to get into the big ring.
Seat tube diameter is correct and clamp size is correct. I would love to hear some ideas from the forum guru's.
Ideas I have (some more drastic than others:
-Slightly scuffing up the inner derailleur clamp
-Tubular rim tape/double side tape
-Spray adhesive like hairspray or 3M adhesive spray.
commo_soulja
04-15-11, 05:39 AM
Is the Pace stuff you've used similar to these?
http://www.jensonusa.com/store/product/CM407B09-Fsa+Carbon+Seatpost+Installation+Compoun.aspx
http://www.jensonusa.com/store/product/TL289H01-Fsa+Installation+Compound+For+Carbon.aspx
http://www.universalcycles.com/shopping/product_details.php?id=30551&category=205
Barring that, maybe a thin shim would do.
b16a2nr, I have a single layer of electrical tape under the band on my T bike, tho' it wasn't as severe an issue as yours.
Brad
b16a2nr
04-15-11, 01:07 PM
That is the paste I used. I'm afraid that electrical tape adhesive is to oily and gummy and will eventually break down and slide.
b16a2nr
04-15-11, 09:19 PM
I tried a piece of bike tire tubing between the clamp and seat tube and it still slipped. Next on this list is tubular rim tape.
another idea, how about clamping another clamp beneath the FD clamp?
This should keep it from slipping down, but I'm not too sure if it will keep the FD from slipping side to side.
rogerstg
04-16-11, 05:04 AM
That is the paste I used. I'm afraid that electrical tape adhesive is to oily and gummy and will eventually break down and slide.
Masking tape works well for shimming. It's thin and dense and does not have the rubbery "give" of many other tapes. I've it for FDs as well as other things.
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