|Triple front derailleur woes. Help?||lokstah|
Aug 27, 2003 11:31 PM
My girlfriend has a new Specialized Allez Vita Women's; it's got a mixed triple drivetrain (Ultegra RD, Ultegra short reach STI, Tiagra FD, Specialized cranks/rings). Anyways, I'm not too famliar with triple drivetrains and the FD is behaving funny. I can't seem to fix it.
The FD seems to have four positions -- 1 (on the small ring), 2, 2.5, and 3. Positions 1, 2, and 3 are perfectly dialed in and run a wide range of rear cogs well. 2.5, however, is a nuissance, and it's useless. In any configuration which sees the upper and lower limits set correctly, 2.5 serves one role: the middle chainring position on which the chain always rubs the inner cage surface, even when in the smallest cog. It doesn't function as a "higher gear incremental positon" for the middle ring at all, and it doesn't need to... position 2 works fine. I wish I could just eliminate the extra position...
Any ideas? It's tempting to think that simply spending the price of a tire on an Ultegra FD will solve the problem, though that may be too easy. Help? Thanks a bunch.
|re: Triple front derailleur woes. Help?||Rusty Coggs|
Aug 28, 2003 4:59 AM
|Positions are not in the derailer.If you don't need 2.5,don't use it. An ultegra FD will solve nothing. The 2.5 is in the shifter. It's a trim position isn't it? If so just ignore it.|
|re: Triple front derailleur woes. Help?||edmundtan|
Aug 28, 2003 5:17 AM
|The 2.5 position is likely to be a "trim" position for eliminating chain rub with the FD cage when the chain is in the biggest ring and larger cogs combination.
Download the instruction from the Shimano Europe web site: http://www.shimano-europe.com/cycling/phpimages/productserie/service_pdf/SI-6C80C-EN.pdf
Alternatively, get advice from a good bike wrench at your favorite lbs.
|re: Triple front derailleur woes. Help?||lokstah|
Aug 28, 2003 8:22 AM
|Thanks guys. Naturally, I don't know how to modify the trim myself, so I'll have to turn to one of my more inclined buddies for help.
Unfortunately, it's difficult in most situations to simply ignore the 2.5 position; the way things are currently trimmed, for instance, though the "2" position is an ideal "running" position, it's extremely easy to push the chain from 1 into 2.5 when meaning to hit 2, and at the same time, often difficult to move the chain from 1 simply by going into 2 (ie, the 2 position seems as though it needs to be trimmed higher).
Shifting from the small ring to the middle ring almost always involves going from 1 to 2.5 and immediately down to 2.
Aug 28, 2003 10:01 AM
|The second and third positions should lie on either side of the middle ring. They are to trim the derailleur to avoid chain rub.
When shifting from the small chain ring to the middle ring it is normal to need to go to the third position in order to get the chain to climb up on the middle ring. Then depending on which cog you are using in the back, you may need to shift back to the second position to avoid chain rub. On a triple you need all four positions (detents).
There is also friction trimming up to 5mm available by simply bumping the shift levers.
I also recommend that you read the information at the shimano.com European Bike site.
(This is why I prefer doubles.)
Aug 28, 2003 12:24 PM
|Thanks; makes sense. I still think something needs to be adjusted, at present; the third (or 2.5) position is too "high" to run on the middle ring without chain rub no matter what the cog selection. It is, at present, useless, particularly because I can access the entire cassette without rubbing from the second position.
Thanks for the information, all. I'll read through the Shimano documentation.
Aug 28, 2003 1:43 PM
|Sounds to me as if you need to re-connect the cable at the front derailleur. Shift the chain to the smallest chain ring and biggest cog. Disconnect the cable from the front derailleur. From the derailleur end pull the cable out of the shifter while shifting the small lever (left shifter) several times to make sure all of the cable is out of the shifter. With all of the slack pulled out of the cable re-connect to the derailleur. Read the instructions at www.Parktool.com.
Aug 29, 2003 5:12 AM
|I've answered this question in various forms so many times that I've grown tired of typing up the whole procedure. The most common problem that I've noticed with front derailleur adjustments is that guys don't want to start at the beginning. As a result, they keep making misadjustments to correct their previous misadjustments and never do get it right.
Disconnect your shift cable, check the Parktool website, and start with the position of the derailleur on the seat tube and setting the low gear limit stop. It'll work fine.
Aug 29, 2003 8:40 AM
|.. follow the instructions, in order from start to finish, and you're dérailleur should work perfectly!
Aug 29, 2003 11:05 AM
|Thanks everyone. I'll walk through this. Seems pretty straightforward.|| |