Shifting problems w/new compact crankset

[jenxxs]

Hi everyone,
Well, after almost 4 hours of derailleur fiddling, I'm proud to report that I have figured some things out! I found a key piece of advice from the FSA website - they suggested raising the front derailleur 1-2 mm higher than the normal recommendation, to solve the chain drop problem. This seems to work for me - the derailleur now sits 2 dime-widths above the big ring teeth, versus 1. It does slow down the shifting, but the shift is much cleaner (chain not bouncing around like crazy), so I think I can live with the slower downshifting.

In the process of undoing and reattaching the cable many times (where I had zero prior experience), I seem to have created another shifting problem having to do with the indexing. Both my downshifting and upshifting now take 2 pushes. From big to small, the first push moves the chain, but then after the shift I have to push the lever again (same direction) to trim it. From small to big, the first push moves the derailleur closer to the big ring, and then it takes a second push to get the chain up to the big ring.

Could I somehow have messed up the indexing of my STI levers while undoing and reattaching the FD cable?

Well, at least this new problem is less annoying to me than the chain dropping all the time!

[DebW]

That's probably the way it's supposed to be. The trim shifts account for the fact that you need different FD positions for different RD positions. For the small-to-large FD shift, you should already be on the 1st trim click if you are on an outer rear cog with the inner chainring. Then it would be only one click to upshift the FD. Likewise moving the other way. For a large-to-small FD shift, if you were on an outer rear cog, you'd stop with one click of the FD, but if you were on an inner rear cog, you'd need 2 (or would be at the intermediate trim to start with.

[roadfix]

My guess is also a simple adjustment problem. There is really no reason why your set up can't be almost perfect.

[jenxxs]

Well, 9 hours of off-and-on fiddling later, I think I have it set up reasonably well. Turns out my indexing problem was caused by not tightening the cable enough - I also didn't realize the cable would have a larger effect on the cage shifts than the limit screws.

Thanks to all of you for encouraging me to try this myself - I learned a lot this afternoon by trial and error! Lots of error

[roadfix]

Well, 9 hours of off-and-on fiddling later, I think I have it set up reasonably well. Turns out my indexing problem was caused by not tightening the cable enough - I also didn't realize the cable would have a larger effect on the cage shifts than the limit screws.

Thanks to all of you for encouraging me to try this myself - I learned a lot this afternoon by trial and error! Lots of error

Glad you got this up and running. You can practically throw away the limit screws but if you don't have proper cable tension, nothing will work right.

[Rai Sue]

glad you found the easy fix of adjusting cable tension. Folks having chronic problems switching from the smaller chainring up to the larger chainring in the front may also want to look into seeing if their larger chainrings have pins and ramps.

Pins are little steel bumps on the back of your chainring (facing the smaller ring) which give a little boost to the chain. Shimano makes them, so you can change out the chainring to one with pins. It totally solved my problem of the chain not switching up, even when the derailleur and cable were adjusted.

Ramps i think are little divots in the back of the chainring itself which help facilitate lifting the chain up.

You can read more about it (and see a picture!) at http://www.sheldonbrown.com/gloss_ra-e.html

[jenxxs]

While I made sure to get new rings with pins and ramps (Stronglight), I have to say that the ramps aren't nearly as effective as those on the Ultegra ones I took off. Those ramps are huge, and they worked flawlessly. I'm sure Shimano also optimized their pins/ramps to work on their matched ring sizes.

Do other manufacturers of compact-sized rings (like FSA) have matched sets with really good pin/ramp systems? Since I was going with 48/34, which is not the most popular combination, I didn't try to look for a matched set.