So my new 12speed SLX started shifting appallingly. Set up fine on the workbench every time, then mid ride it won’t shift up, won’t shift down, then it’s ghost shifting randomly at the small end of the cassette. Get home, start again. Shifts perfectly until a few miles into the next ride and then all goes to pot. Cables fine, bought a hanger alignment tool, hanger is fine. Derailleur is fine. Two months this has gone on for and the whole bike is only 600miles old. Problem? It’s a Canyon Spectral. It came with a bolt through rear axle. I bought the jazzy quick release Quixle. Fitted that. Shifting went to pot. Has an epiphany yesterday when I remembered it went crap after I fitted the Quixle. Put the bolt through back in yesterday and today the shifting is absolutely perfect.

Why? Why would this happen?

Are they the same dimensions?

The qr axle is not straight?

Is the QR pulling everything together nicely

Im going to hazzard a guess on a sticky clutch. Has all the symptoms you describe and can be fickle, sticking and then unsticking based on a myriad of things. Changing out the axle which would mean maybe fiddling with clutch and or mech arm would be enough to free it up, this time…

I have an SLX 11 spd clutch mech and get these exact symptoms on my Cotic Flare. I’ve re-indexed and adjusted it numerous times on the workstand and had it perfect, then gone for a ride or maybe two and it’s back the same again, so start over. Mine would sometimes stick when it got into the lowest gears so cage was at almost full extension, then not return fully, so the chain would be slack AF/jump off when you shifted back down the block.

I had the clutch cover off and thoroughly cleaned/de-crusted/lubed it all and it seemed to fix things, but for how long who knows.

I serviced the clutch. Set the high and low limits and the B-screw as per the dealers manual. I can only assume the Quixle isn’t quite the right dimensions and the rear triangle is flexing too much or something daft.

I can tell you that if the clutch is set too tight it will knacker the shifting. Seems to pull the derailleur against the next biggest cog on the cassette.

12 speed is rubbish in my opinion. Too many cogs too close together and not enough room for mud/grass/twigs/slop. Thinking about giving the Box Prime 9 a go.

I think we need to start a petition to get Shimano to release their gear box or maybe all come together to bulk buy some Pinion gearbox’s (and frames obviously)

What happened to cheap gearbox bikes?

Arghhhh 12spd!!!

work of the DEVIL