Old 03-29-11, 12:17 PM
  #14  
FBinNY 
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Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,706

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

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Just to get on the same page. I'm assuming the FD is sprung to shift in on the spring, and out with the cable. If it's the reverse, stop here and disregard the post.

Also because it works on the stand but not on the road, I remind you that the FD works on the tense loop of the chain and therefore cannot lift the chain over the teeth of the outer cog if you don't ease up pedal pressure to reduce chain tension enough. Try totally backing off pedal force during the shift and verify that it's mechanical and not you.

Since the FD moves inboard on spring power not cable and the cable is slack at the down tube, and not binding at the BB shell something other than the cable is the problem. Verify this, by removing the cable entirely and shifting by pressing on the FD's lever arm to shift and observing if it moves back in quickly and positively. Also check that it goes fully to the inner limit, by varying the limit position and checking that it causes changes in the cages innermost position. If not something else is binding the pantograph or limiting it's innermost position.

If you have any doubt at all move the chain out of the way, and work the FD back and forth against the spring. It should snap back very sharply with zero hesitation, and bang hard on the limit. Flush with solvent and oil with light oil until it does.

Now if you've confirmed that the FD itself is OK, start fresh checking height, alignment and cable settings, you should be able to get it right.
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