As a keen mtb fettler and having installed and maintained approx 20 cassettes, 3 different derailleurs, built a bike from scratch etc with the associated indexing required, I think I’ve got a pretty good handle on this sort of mechanics.
I took the plunge into road biking this year an got a Defy with 105 shifters. These have worked perfectly for 6 months but now can only be described as ‘sloppy’.
So working through the options I:
Installed new 105 cassette and chain.
Straightened hanger, then bought a new one anyway.
Cleaned and lubed all the cables, including unwrapping the bar tape and lubing the shifter mech.
Yet still the shifting is imprecise.
Basically I can get it to move accurately down from the big cog to the smallest responding well to each click, but then it takes a double click to start the return and when riding I’ve lost the reliability of click-shift. Now have to ‘feel’ it in with the large lever.
It’s all very frustrating. I bought 105 because I thought it was comparable to xt quality, have I been mistaken? Is this a case of flogging a dead horse and an upgrade is the best solution. Is it the shifter or the derailleur that is most liable to be a bit naff?