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Old 05-09-15 | 02:42 PM
  #4  
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

What follows are generic instructions for front derailleurs. The details may vary, but the general principles and methods are basically the same for all.

Start by checking that the outer cage plate is parallel to the face of the outer chainring, and that when directly over the teeth it clears by 2-3mm. There's fudge room, but use this as the starting place, and don't fudge unless you know haw and why.

Set the inner limit, so the inside cage plate just clears the chain when in low gear (granny/big). It helps to take weight off the screw by manually moving the FD out (pull on the cable a bit) so the limit screw turns easier. Make this a habit whenever adjusting the inner limit. In low the FD should be resting on the inner limit, not hanging from the cable, and the cable should be slightly slack.

Move the RD to the outer third of the cassette and shift to then outer front by pulling the wire away from the down tube (ignore the levers for awhile). Back off the outer limit until you can shift to high and beyond, dumping the chain over the outside. Now trial and error bring the limit in by degrees, testing by pulling the wire until you cannot overshift. Test this a number of times and if in doubt you can bring the outer limit in another 8th turn, but no more.The goal is to find the outermost setting that prevents overshifting. Now the manual shifts from mid ring to high should be clean and crisp.

Now that both limits are set, adjust the cable trim. (now is when you'll first use the levers) This is easier with a barrel adjuster, otherwise you need to loosen and reset it at the pinch bolt. various mechanics have their own version of "best" for the trim adjustment, and the details will vary if, for example, the lever offers a trim click. However my general preference is to adjust according to high gear trim, so shift to high in the back, and adjust the trim so the outer plate just clears the chain, then test for crisp shifting. My preference is for the innermost trim that clears the chain and shifts crisply.

Lastly, test shifting and trim on all sprockets, which should be close, but may need a tweak. Likewise the inner limit might need a slight tweak for clean shift and trim in low.
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