Had to replace my chain and the front chainrings on my Canyon Ultimate (11-speed mechanical shifting, Ultegra R8000), so I decided I also wanted to throw on an 11-34T in the back. From what I have read this is fine to do with my particular short-cage derailleur.
However, Shimano's usable 11-34T cassette for my drivetrain, the HG700, is made to be used on both 10-speed and 11-speed drivetrains. Supposedly, according also to what I have read, mostly on reddit, for my 11-speed situation I therefore require a spacer, which I bought.
I gave everything to my mechanic. My LBS mechanic was thoroughly convinced that the spacer is not needed. I asked him to install it anyway to humor me. When I picked up the bike, though… well, he didn't install the spacer. Again, he insisted it was not needed. I tested the bike out on a few blocks around the shop (very flat area), and shifting was good, so I figured he was right. Intuitively, it makes a kind of sense: a spacer seems like it would only be needed in cases of 10s.
But then I took the bike out for climby rides today and yesterday, and the shifting under heavier chain tension was not so great. Especially in the higher tooth gears. Just very noisy and clunky.
I quite like my mechanic and he's done great work in the past. I'm sure he would reinstall the cassette with spacer as part of the included cost of the labor I already paid (the real thing I'm paying for here is the indexing of gears, TBH), but I feel like I should REALLY be sure that this is the right move if I ask for it. I don't want to go through the hassle and additional expense of finding a new mechanic.
What is the right move here, and why? TIA.
by bugg_nn_out
2 Comments
Just tell him it shifted badly under pressure and you would like to try it with a spacer… that being said; replacing a cassette yourself is suuuuper eesy
We can have theoretical discussions all day long, in the end the only thing that matters is “does the cassette lock nut bottom out before tithening the cassette ?” if yes then it needs the space. 100% your mechanic knows this. If you want to double check, see if the cassette cogs wiggle individually or not. The bad shifting can just be the lack of derailleur tuning after replacing the cassette.
All in all just tell your mechanic the shifting is bad and let him fix, don’t micro manage him.