Unusual wheel failure

[figbat]

I went out last night for my weekly ride with the village MTB group, looking forward to ~20 miles in good weather and a pub at the end. Unfortunately after about 5 miles we were in a wooded area on some singletrack and I caught an exposed stump - there was an immediate rubbing sound from the rear tyre on the frame so I stopped.

I thought that the QR had shifted so loosed and refitted it but this didn’t help. On removing the wheel completely it was obvious the axle was knackered so I called for recovery and the group went on without me.

At home I investigated further and found the problem:

This is, or was, a QR adaptor on the end of the axle. It’s a Superstar V3 hub with a through-axle which is adapted for QR by one of these each end - this was on the drive side. I have a new pair on order and as far as I can tell, pushing a new one on will fix it. It’s a thin gauge of metal though.

 

[raleighnut]

You'd think they would machine it from a single piece that pushed in with a hole for the skewer, that design looks crap

 

[T4tomo]

looks like weight saving exactly where you dont need it!

 

[C R]

You'd think they would machine it from a single piece that pushed in with a hole for the skewer, that design looks crap

You may get away with it in a road bike that only sees smooth surfaces, but in an MTB I expect it will break regularly.

 

[Dogtrousers]

I'd buy a couple of new ones. And carry a spare

 

[figbat]

I'd buy a couple of new ones. And carry a spare

That’s what I thought, but to replace the drive-side one requires removal of the cassette lock ring - I tend not to carry a chain whip and lock ring tool!

 

[figbat]

Just to add, my recall of the event is that I caught the drive side crank on the stump - and hard - I assume this transferred the shock load down the chain to the cassette and hub and this possibly-weakened adaptor sheared. As someone else put it last night, at least it saved the axle/bearings etc but as noted above, it’s an MTB hub that ought to be able to take a knock.

 

[Dogtrousers]

That’s what I thought, but to replace the drive-side one requires removal of the cassette lock ring - I tend not to carry a chain whip and lock ring tool!

OK, then at least keep a spare at home. Which, if you are anything like me, you will be unable to find when you need it.

 

[C R]

Just to add, my recall of the event is that I caught the drive side crank on the stump - and hard - I assume this transferred the shock load down the chain to the cassette and hub and this possibly-weakened adaptor sheared. As someone else put it last night, at least it saved the axle/bearings etc but as noted above, it’s an MTB hub that ought to be able to take a knock.

Regular inspection of the state of the adaptor may be needed to catch failure before it happens. Probably a bit of a ball ache if you need to take the lockring out to inspect.

 

[si_c]

That’s what I thought, but to replace the drive-side one requires removal of the cassette lock ring - I tend not to carry a chain whip and lock ring tool!

Well, this might help.

 

[figbat]

Well, this might help.

That's genius! I assume it works by jamming the locking to the dropout and then you turn the crank, having selected 1st gear? I can see how this could cause worse damage but if used judiciously it seems like a good idea.

 

[figbat]

Regular inspection of the state of the adaptor may be needed to catch failure before it happens. Probably a bit of a ball ache if you need to take the lockring out to inspect.

It will certainly be added to my list-of-things-to-check-when-I-do-a-more-involved-once-over.

 

[figbat]

OK, then at least keep a spare at home. Which, if you are anything like me, you will be unable to find when you need it.

I tend to find the thing that I was looking for last time when I am looking for the thing that I need this time.

 

[Threevok]

Does look a bit thin. The ones on my Hope Pro 4s are a lot thicker, although these also aren't one piece

 

[figbat]

Does look a bit thin. The ones on my Hope Pro 4s are a lot thicker, although these also aren't one piece

Yeah - one of the guys I was riding with said the same about the ones he has. They are sold as hub-specific although no doubt trial and error would come up with an alternative.