Knocking off the rust
Join Date: May 2006
Bikes: LeMond Tourmalet, Specialized Tarmac
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Odd shifting problem
When I am in the big ring I cannot upshift to the last cog on the cassette (the 12T). Click the shifter, but the chain does not move down to the last gear.
When I am in the middle ring it shifts instantly to the 12T (and all the others for that matter). Other than this problem, the system works absolutely flawlessly - crisp, instantaneous shifts, almost silent in every gear and I have never dropped a chain.
The patient is a 105 triple with 30/39/50 and 12-25, running a SRAM chain.
So what would cause this very odd problem? I am hesitant to back-off the the lower limit screw since I can engage the last cog in the 39 ring, and I do NOT want to risk throwing a chain into the gap between the last cog and the frame and locking up the rear wheel at 40mph.