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STI Shifting Problems(3 posts)

STI Shifting Problemsjagiger
Aug 21, 2001 6:13 PM
My bikes got Ultegra group & it was starting to get a little rough shifting up through the low-mid cogs.

I thought that I would try to do the adjustments. I found that the adjustments must be really fine, as I really messed things up. I never could be sure whether the upper & lower adjustments actually were actually doing anything. I must have over tightened or loosened the set screws & now I cann't get into the 2 largest cogs or the smallest either. Unfortuneately, I had this bright idea just before today's ride & finally decided to go out cause it looked like rain.
I need help to get things going right again. Where do I go from here? Thanks
Solutions, maybe.Atombomber
Aug 21, 2001 6:48 PM
THe easiest way is to take the bike to a shop and get them to adjust everything again. Have them check the deraileur hanger for proper alignment too.

If you want to tackle it yourself, you'll have to understand the priciples behind cable actuated shifting. As the cable is tightened, it moves the deraileur towards the centerline of the bike (unless it is Rapid Rise XTR). The screws you tightened are the limit screws, preventing the deraileur from moving beyond a certain point. The barrel adjuster takes up or lets out cable, depending on how you want to move the deraileur. If for some reason (crash, tipped over bike, stick) that the hanger that holds the draileur to the frame gets bent, it will throw the shifting out. If dirt or other contaminants get into the deraileur, shifting could go awry. If the actual deraileur is bent, get a new one.

First you must make certain the hanger is straight, using the proper tool. If/once that is OK, then unscrew the limit screws. Downshift so that the chain is on the smallest cog, and tighten the limit screw so that the deraileur pulley (jockey) wheel is directly under the smallest cog. If the pulley is still between cog 1 and 2, and the limit screw is still not screwed in, then you must check the cable tension. There should be a bit of slack. Screw the barrel adjuster in to get more slack, so that the pulley lines up under the smallest cog. Once you have a base to start with, shift up one click at the lever. If the chain goes up one cog and rides over the cogs quietly, shift to the next one, and so on until you reach the top. If the chain sounds like it didn't go far enough, take some slack out of the cable by unscrewing the barrel adjuster, until there is no bad noise. Then start shifting to the top and adjusting the cable tension as required to make it go smoothly and quietly. Once all the way at the top, shift down. The chain should drop with each click of the shifter. If it is stubborn, add some slack to the cable. Once you can go all the way down properly, test one gear at a time, click up, click down, move to the next once all is well. Once you have to cable tension done and tested in all the front rings, shift all the way to the largest cog, and set the top limit screw so that the deraileur can't move the chain into the spokes.

You're done.

BTW, it helps to have a good bike repair stand when doing any work on the bike.
Thanks for the help...I got it working againjagiger
Aug 22, 2001 7:42 PM
It turns out that on the Ultegra the adjusting screw is reverse of a common convention that the screw closest or highest is the one for the lowest cog, near the spokes. It did find labeling on the derailluer after I put the flash to it. Oh well, chaulk up another one.

Thanks