You’re the mechanic, apparently. Almost looks like a bearing seized and spun but not sure how you’d accomplish that without locking up the wheel.
Healthy-Inspector-86 on
My best bet you can see the dark lines in the middle right on the axle. It was being worn down by friction and that lead to failure.
iliinsky on
What brand and model, out of curiosity? Was there a bearing right there? Was it in good shape or seized? If you cannot diagnose it, there may be other problems.
FutureDatedReference on
What hub? Some brands/models are know to have durability issues, Stan’s neos or industry nines come to mind, kinda looks like a Stan’s axle to me
opavuj on
Not that uncommon. Even some (most?) $$ hubs aren’t all that durable. I9 I’m looking at you.
Pretty much any hub and or axle will bite the dust if 1) customer rides with axle loose or 2) rides with seized bearings.
dobie_gillis1 on
The achilles heel of rear hub design is its off center bearing placement. All the weight and major forces are being placed on half of the axle.
Jumpy-Birthday8446 on
I’ve done this myself with Hunt Wheels’ hubs and seen it done with others. As others have commented it’s where a bearing grabs once it stops spinning smoothly.
Chap-eau on
It’s a fairly well known issue with Stans Neo hubs with insufficient axle thickness. A stress riser forms at this location because of the location of the supporting bearing and the tangential load from the pawls.
The standard replacement is a steel one.
Almost all hub axles are aluminium (they probably shouldn’t be given their lower diameter) but this is specific to Stans.
IndyWheelLab on
My guess is fretting fatigue. It looks like there was friction at the interface between axle and bearing in that location, weakening the aluminum until failure. Water and corrosion can accelerate this process.
A worn bearing with play or seized bearing could both lead to failure over time. I’m not good enough with metallurgy to look at the crack pattern and tell you exactly what happened, but it’s Reddit so someone with this background might chime in.
9 Comments
You’re the mechanic, apparently. Almost looks like a bearing seized and spun but not sure how you’d accomplish that without locking up the wheel.
My best bet you can see the dark lines in the middle right on the axle. It was being worn down by friction and that lead to failure.
What brand and model, out of curiosity? Was there a bearing right there? Was it in good shape or seized? If you cannot diagnose it, there may be other problems.
What hub? Some brands/models are know to have durability issues, Stan’s neos or industry nines come to mind, kinda looks like a Stan’s axle to me
Not that uncommon. Even some (most?) $$ hubs aren’t all that durable. I9 I’m looking at you.
Pretty much any hub and or axle will bite the dust if 1) customer rides with axle loose or 2) rides with seized bearings.
The achilles heel of rear hub design is its off center bearing placement. All the weight and major forces are being placed on half of the axle.
I’ve done this myself with Hunt Wheels’ hubs and seen it done with others. As others have commented it’s where a bearing grabs once it stops spinning smoothly.
It’s a fairly well known issue with Stans Neo hubs with insufficient axle thickness. A stress riser forms at this location because of the location of the supporting bearing and the tangential load from the pawls.
The standard replacement is a steel one.
Almost all hub axles are aluminium (they probably shouldn’t be given their lower diameter) but this is specific to Stans.
My guess is fretting fatigue. It looks like there was friction at the interface between axle and bearing in that location, weakening the aluminum until failure. Water and corrosion can accelerate this process.
A worn bearing with play or seized bearing could both lead to failure over time. I’m not good enough with metallurgy to look at the crack pattern and tell you exactly what happened, but it’s Reddit so someone with this background might chime in.