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04-22-04, 10:31 AM
Approximately 2 weeks ago while on a ride it was noticed that the rear 105 STI shifter wasn''t working properly. The upshifts (towards the largest rear cog) were fine. But the downshifts (towards the smallest rear cog) required that the small STI downshift lever be pressed firmly towards the left and held there longer than usual. Well, about 3 miles from home the shifter would no longer allow downshifts (to smaller cogs) at all.
That evening while the bike was in the repair stand, I began to work the shifter both in upshifts and downshifts. I carefully observed what was happening and noticed that when the small downshift lever was pushed to the left, the large upshift lever moved to the left as well. But, just a teensie bit. Well we all know that the shifter won't downshift at all if both levers are moving to the left. So, I peeled back the shifter hood and noticed a fair amount of grime in the shift mechanism. It was then cleaned with brake parts cleaner. Then blown dry with compressed air. Next came a small dose of Finish line teflon lube.
This worked. At least for awhile. Last weekend after about 35 miles into a 66 mile ride it started doing the same thing. If the large silver upshift lever is held steady, the small downshift lever works perfectly. But otherwise the large lever moves just a little bit when pressing the small lever, and that movement is enough to prevent shifting. The cables were pulled from their housing. The housing was degreased and relubed. The cables were cleaned and relubed. The bike has about 8,000 miles on it and is generally meticulously maintained.
HELP!! I'lm looking for any advice. Especially from some of our professional wrenches that visit this site.
That evening while the bike was in the repair stand, I began to work the shifter both in upshifts and downshifts. I carefully observed what was happening and noticed that when the small downshift lever was pushed to the left, the large upshift lever moved to the left as well. But, just a teensie bit. Well we all know that the shifter won't downshift at all if both levers are moving to the left. So, I peeled back the shifter hood and noticed a fair amount of grime in the shift mechanism. It was then cleaned with brake parts cleaner. Then blown dry with compressed air. Next came a small dose of Finish line teflon lube.
This worked. At least for awhile. Last weekend after about 35 miles into a 66 mile ride it started doing the same thing. If the large silver upshift lever is held steady, the small downshift lever works perfectly. But otherwise the large lever moves just a little bit when pressing the small lever, and that movement is enough to prevent shifting. The cables were pulled from their housing. The housing was degreased and relubed. The cables were cleaned and relubed. The bike has about 8,000 miles on it and is generally meticulously maintained.
HELP!! I'lm looking for any advice. Especially from some of our professional wrenches that visit this site.