Bicycle Mechanics - Front Derailleur (road bike)
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Getting ready for my first metric century on Sat, I decided to adjust my front
derailleur to make sure everything was in good working order. Of course I screwed it up, it is a triple (Sora sucks). I readjusted so when pedaling on the
trainer by hand it will go to the large chain ring. But when I'm riding the bike
it doesn't want to shift to the large chain ring. Any suggestion would be appreciated, would like to have it working properly before ride tomorrow. Oh,
I did print out some instructions from Park Tools as well. Thanks
What did you do? What is happening? More details might help.
It may be a matter of just adjusting the limit screw for the large ring. I assume you know about the limit screws which stop your chain moving too far and coming off.
If you actually moved the der. or changed the cable, then you may have the cable too loose and you can't get the travel to the largest ring. If so, you need to switch to the smallest ring and tighten up the cable.
The difference between workstand hand turning the cranks and riding torque on the cranks is enough to move the chainwheel out a mm or two, which is enough to interfere with shifting if the take up ramps on the CW are synchronized with the pedal stroke so they are away from the chain when the shift attempt occurs. In order of liklihood of problems (most covered in the Park Tool literature): 1)outer limit screw on FD cage needs to be backed off a bit
2) cable is a bit tight: put chain on smallest CW and largest cassette cog, the FD cable should be under least amount of tension now; Check to be certain the cable housing is fully seated in the down tube cable stop and at the shifter end, then take the barrel adjuster (usually on the down tube cable stop) and screw it all the way in, then back out two turns, finally loosen the cable clamp on the FD and pull the cable tight with plyers and reclamp the cable. Make sure the cable is clamped in the right groove in the clamp. 3)Torque the CW fixing bolts and the crank fixing bolts just to be sure they are tight.
All of this assumes the FD is at the right angle and height in relation to the CW. Adjustment of this is covered in the Park literature. Steve
On the barrel adjuster, turning two full turns or two clicks? When in the small
CR and large cog the cable should be loose, but you are telling me to tighten
it up (take up the slack). So as you shift to large CR it will get tigher, correct?
On the barrel adjuster turning counter-clockwise tightens the cable & clockwise
loosen it correct? Sorry for all the dumb question, just want to verify. I do understand about the limit screws, but it seems the the H-limit screw is backed
out quit a bit. Thanks for the help.
Mea culpa. I gave you the set up for the RD barrel adjuster, the FD barrel adjuster should be screwed all the way in, and has less adjustment range than the RD adjuster. Sorry for confusing the two, and you. The FD barrel adjuster is used to take up slack that develops after a few hundred miles, cables always stretch a bit. The FD adjustor has several (3) click stops, use the one that doesn't add any cable tension. As I noted, the cable should be set up for no slack when the chain is on the smallest CW and the cage positioned as per the Park photos when the chain is on the small CW and largest cassette cog. That is the starting position for the shifter system. Steve
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