So, I bought a new bike, a Canyon hardtail, which replaced my 20 year old M-Trax.
My first big ride was taking part in the Ratrace Crossing C2C event last month.

I’ve done something like 300 miles on the Canyon and guess what; the rear wheel bearings are shot!! (the Formula R1 rear pads have also had it, but that’s another story…).
Can anyone recommend some good quality wheel bearings for the SLR 29’s please?
BTW, the old cup and cone bearings in the Mavic wheels fitted to the M-Trax are doin’ just fine after 20 years of use. New is not always better….

Having recently popped out the two rear wheel bearings and replaced the two in the freehub, I can recommend the Mavic site for an excellent exploded diagram, youtube for service instructions and Kasea on here ( katec components) on ebay for bearings. Mine arrived next day.
I suspect you just need to pop out and regrease after such a short time.

Thanks for the advice. I’ll try and re pack them with grease.

Have you read the manual, mavic bearing will need adjustment after a few hundred miles and you should have got the tool with the bike.
the bearings are only dead if they are rough and graunchy.

I had similar issue with the bearings on my ST 29’s after a short time there was appreciable movement at the rim. Tightened using key and was OK for a bit, kept on requiring tightening though as the nut loosened? Following advice I put a small dib of Loctite on the nut and it has been fine ever since and the bearings themselves seem very smooth still so no permenant damage I think.
I had phoned Canyon service centre, they suggested taking to a Mavic dealer to check over, implied would pay for any work needing to be done.

kept on requiring tightening though as the nut loosened

overtightened

common error, there’s a sweet spot that won’t loosen – basically if you’re tightening till there’s no side to side play, its too tight (as the play disappears once you add rider) the correct way to adjust is to spin the wheel, then wind on the preload till you see the wheel begin to slow/resist – then back off the tension about a quarter to half a turn for correct tension.

Ninfan, I have two sets of these wheels, no issues at all with the first which have been on my Cotic for 15 months, and I always have adjusted them as you suggest. Still came undone on the Canyon wheels. But thanks for the suggestion