Dear Bruce:
There's not two sizes of clamps as far as I know. I diagnose that you are a victim of the French Disease: making everything just a leeetle bit different: a malady that drives bike nuts nuts.
I strongly suspect your problem is that the Motobecane is using a French sized seat tube, which is just pinch smaller than Italian standard sizes. That would account for your derailleur not quite drawing tight and the bolt running through too far. The only fix I know of is to use a french derailleur or adding few wraps of tape around the tube to build up the diameter to fit the clamp.
BTW, I suspect the reverse of this phenomenon explains the bunches of simplex derailleurs with broken clamps: trying to tighten them up on "oversize" Italian and English seat tubes.
Tom Adams Manhattan KS, USA
bruce thomson <masi3v4me@yahoo.com> wrote: Listers is there a tubing diameter difference in the FD clamp on NR/SR front dérailleurs? Who can you tell about the clamp size by looking at the FD? I am finishing my Motobecane Grand Record and the clamping strength is weak with too much bolt passing through the clam-down. BT
Bruce Thomson Spokane WA 99204 (509) 747 4314 Masi3v4me@yahoo.com
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