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Old 07-29-14 | 06:18 PM
  #19  
FBinNY
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Joined: Apr 2009
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From: New Rochelle, NY

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Originally Posted by robabeatle
Haha...love it. I should have mentioned that the autoshift issue occurred when out of the saddle rocking the bike back and forth with some gusto.
OK this points directly to a short list of likely suspects. It's possibly a case of "raise the bridge or lower the water".

Normally, shifting would happen if the FD cage moved over a bit, but instead the crank is probably moving out a bit at the top (compared to the FD cage).


Next time you hammer look down at the chain, ring and front derailleur. You notice movement of the ring compared to the FD cage. If so, that's the problem. The cause is a bit harder. It could be frame flex, crank flex or a loose BB, so you still have some detective work to do.
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Last edited by FBinNY; 07-29-14 at 06:34 PM.
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