To clarify, this is not a request for support, I’ve already fixed the issue. I’m posting this just to provide a cautionary tale, and info for anyone in the future who might have to deal with this.
I’m a big dumb dumb. While riding on my Canyon Grizl 6 AL on my direct drive trainer, I stripped out half of the threads on the rear thru-axle frame hole. Best theory I’ve got is I’ve been over tightening it over a long period of time, slowly damaging the threads, until the high torque, low cadence, out-of-saddle workout, rocking side to side, finished them off. I had the trainer on a thick yoga mat, with the tennis ball mod. I think it was also compounded by Canyon specifying a thru axle (158mm) that only engaged half the threads.
After soliciting input from a bunch of people, mechanical engineers, bike shop mechanics, you name it, and pulling my hair out, I opted to change axle pitch from 1.0 to 1.5 and use a Timesert thread repair insert. This was the option that retained stock functionality while still presenting full strength threads (if not stronger-than-stock), with low risk of the repair failing from frequent use.
I’ve realized the Timesert is the ONLY thread repair that would have worked in this application. The derailleur hanger indexes on a cylinder of aluminum protruding from the frame, which is drilled and tapped and through which the thru axle threads. Drilling out the damaged thread would have left it painfully thin walled with a helicoil repair. Using a Timesert, you outright remove that, leaving the axle hole interface flush, and replace it with the Timesert itself. Ezlok doesn’t have the continuous top lip of metal to index the hanger, so that wouldn’t work either.
I used an adjustable hand reamer bore out the hanger hole on my derailleur hanger to fit perfectly over the insert, indexing it tightly and preventing any movement. I adjusted in fine increments and continually reamed it until it fit perfectly.
Hopefully no one else has to go through this nightmare, but if they do I hope this post helps. Learn from my lesson. If you take your rear wheel off frequently, say to mount on a trainer, keep an eye on your threads, and make sure you aren’t going Shrek on it when tightening. I’d also recommend upgrading to a longer axle. For whatever reason, likely to permit the use of that dumb cosmetic cover, Canyon specs a thru axle that only engages HALF the threads in the frame. That’s just stupid, and I’m pretty frustrated with them on that design decision. Get something that pokes out a bit and engages all of the threads. A 167mm axle with a 3mm spacer works perfectly.
I’m happy to say the bike is now fully functional again. Only thing I have to keep in mind now is to check my axle torque more frequently, as coarse 1.5 pitch threads back out more easily than the stock 1.0 fine threads.
UsedFuture8215 on
Buy a new derailleurhanger, buy the appropriate thru axle, Change the derailleurhanger, use the appropriate thru axle, thats it
I use the thru axle from Canyon on my smarttrainer in the third Winter, and have No problems
HelloWorId1337 on
I managed to do the same thing on my new Grail, maybe not as bad… But I’m not sure what caused it… It was only in the trainer for a day and I didn’t do any hard riding on it and used a torque wrench… Maybe the axle wasn’t 100 straight or there was some dirt in the threads but I struggled hard to get it back out and the threads are a bit damaged but I didn’t had any problems to put the wheel back on
3 Comments
To clarify, this is not a request for support, I’ve already fixed the issue. I’m posting this just to provide a cautionary tale, and info for anyone in the future who might have to deal with this.
I’m a big dumb dumb. While riding on my Canyon Grizl 6 AL on my direct drive trainer, I stripped out half of the threads on the rear thru-axle frame hole. Best theory I’ve got is I’ve been over tightening it over a long period of time, slowly damaging the threads, until the high torque, low cadence, out-of-saddle workout, rocking side to side, finished them off. I had the trainer on a thick yoga mat, with the tennis ball mod. I think it was also compounded by Canyon specifying a thru axle (158mm) that only engaged half the threads.
After soliciting input from a bunch of people, mechanical engineers, bike shop mechanics, you name it, and pulling my hair out, I opted to change axle pitch from 1.0 to 1.5 and use a Timesert thread repair insert. This was the option that retained stock functionality while still presenting full strength threads (if not stronger-than-stock), with low risk of the repair failing from frequent use.
I’ve realized the Timesert is the ONLY thread repair that would have worked in this application. The derailleur hanger indexes on a cylinder of aluminum protruding from the frame, which is drilled and tapped and through which the thru axle threads. Drilling out the damaged thread would have left it painfully thin walled with a helicoil repair. Using a Timesert, you outright remove that, leaving the axle hole interface flush, and replace it with the Timesert itself. Ezlok doesn’t have the continuous top lip of metal to index the hanger, so that wouldn’t work either.
I used an adjustable hand reamer bore out the hanger hole on my derailleur hanger to fit perfectly over the insert, indexing it tightly and preventing any movement. I adjusted in fine increments and continually reamed it until it fit perfectly.
Hopefully no one else has to go through this nightmare, but if they do I hope this post helps. Learn from my lesson. If you take your rear wheel off frequently, say to mount on a trainer, keep an eye on your threads, and make sure you aren’t going Shrek on it when tightening. I’d also recommend upgrading to a longer axle. For whatever reason, likely to permit the use of that dumb cosmetic cover, Canyon specs a thru axle that only engages HALF the threads in the frame. That’s just stupid, and I’m pretty frustrated with them on that design decision. Get something that pokes out a bit and engages all of the threads. A 167mm axle with a 3mm spacer works perfectly.
I’m happy to say the bike is now fully functional again. Only thing I have to keep in mind now is to check my axle torque more frequently, as coarse 1.5 pitch threads back out more easily than the stock 1.0 fine threads.
Buy a new derailleurhanger, buy the appropriate thru axle, Change the derailleurhanger, use the appropriate thru axle, thats it
I use the thru axle from Canyon on my smarttrainer in the third Winter, and have No problems
I managed to do the same thing on my new Grail, maybe not as bad… But I’m not sure what caused it… It was only in the trainer for a day and I didn’t do any hard riding on it and used a torque wrench… Maybe the axle wasn’t 100 straight or there was some dirt in the threads but I struggled hard to get it back out and the threads are a bit damaged but I didn’t had any problems to put the wheel back on