Quoted post said:Originally posted by vansiclenr
My Ultegra STI shifter for the front derailleur is slow to shift up to the big ring (double, not triple) requiring a lot of cranking: One or two big cranks, hold halfway, then another crank. Then, once it's on the big ring, it won't shift down. I can usually fix this by grabbing the wire next to the down tube and yanking while I try to shift. This rather defeats the purpose of STI!
I replaced the cable, lubed everything, re-did the set up several times (taking the tension off the cable by releasing it from the lock screw on the derailleur, backed the set screws all the way off, then re-tensioned the whole thing).
Beyond replacing the cable, I haven't messed with the shifter itself. All the magazines suggest avoiding these fussy mechanism with its 100 parts. But I'm willing to try.
All ideas welcomed. Thanks.
Van
when you say a lot of cranking, you mean revolutions of the crankset? like 3 whole revolutions? does this happen everytime you try and shift or just while shifting under load?
imo, this doesn't sound like a shifter issue since going to the big chainring is just pulling the cable. i'd say that either your chainrings/chain are worn and so the little pins and stuff aren't engaging right, or your front deraileur is either worn and the cage has lost some rigidity to properly push the chain over or not tightened enough to the seat tube.
the first scenario is, imo, less likely since even before those little pins came about 3 revolutions to shift was excessive. try comparing your deraileur to another by gently pushing the cage side to side to see if there is significantly more "play". they do wear out over time and use. easy test, swap the FD and try the shifting again.
the downshifting issue could also be the deraileur. either the cage issue or a worn out spring could cause the inability to downshift without assistance.
i'm hoping it's your deraileur as it's a lot cheaper to replace than the shifters!