How exactly does one snap the rear hub axle?

OK, when I say horror show, I was referring to the image which should have been embedded, not the messed up link that I've actually posted.

Yep that is grim (the link in the second bit works)

It looks like that has been failing for a while. It looks like a series of events have caused the partial failure of the axle - right up to the point where all the partial failures have connected and 'Boom!'

Can't see the pics, but snapped hub axles were a thing all the time with original Pro2 hubs, particularly on Orange 5s where the supplied 12mm thru-axle was narrower in the middle.

There's a massive stress riser in the middle of the axle on most hubs with "pull off" type freewheels - essentially the inboard hubshell bearing is supported on a cantilever the width of the freehub, rather than the whole hub being supported on the bearings at the outer ends like Shimano ones are. Clamping the whole thing tightly together with the bolt-thru axle helps, but if the hub has ever been run with a loose thru axle, I can see a crack starting easily enough after a hard landing.

(I never broke an axle, but back in my freeride days, all my Hope freehub bodies had gouges from the ratchet ring catching on the freehub during hard landings when the axle flexed)

Yep, as per JonEdwawrds. That's exactly where I would expect it to break. Only possible solution for most hub designs is a steel axle if it isn't already.

Exceptions are Chris King and KOM hubs where the freehub body extends in to the hub shell.

Yup, that's how they normally fail.  The drive side hub bearing is the most loaded, but also the least supported. 

Hope resolved it by making the bearings larger ID and having their own internal axle rather than letting the bearings run directly on the frame's axle.

<img> https://www.jejamescycles.com/content/products/hope-hope-conversion-kit-for-pro2-evo-rear-hub-12mm-thru-axle_6457665.jpg </img>

Stans Neo by any chance?

Pretty sure the axle is alloy rather than steel but I'll check when I get home.

I guess what I'm really wondering is whether simply fitting a new axle will sort it out of whether there's a deeper seated issue that would need rectifying first.

I've emailed Hunt for their opinion.

What JonEdwards says makes sense. The axle was certainly tight when I removed the wheel but I wonder whether the seized pivot bearings might have caused the axle to loosen off slightly.

I did remove the rear wheel fairly recently, I can't remember whether it was properly tight or not. It certainly wasn't loose loose, I'm sure I'd have noticed.

I'm going to clean it all up and try the (non broken) end of the axle in the hubs he'll bearing to make sure it's a good fit and hopefully buy a replacement axle if I can find the right one on Hunts site.

Either that, or cut my loses and buy some different wheels. I'm sure it's justifiable...

As someone who managed on a nearly new hub to punch a freehub pawl through it's case, through a bearing and then dent into the alloy axle a few weeks ago, nothing surprises me anymore! I think my axle bent/flexed, and that was enough for the freehub to move around and play nasties...

snapped hub axles were a thing all the time with original Pro2 hubs, particularly on Orange 5s where the supplied 12mm thru-axle was narrower in the middle.

Wasn’t there a massive redesign in the aftermath of that?

Hunt have a good reputation for being good for warranty claims. Have a word with them 

Wasn’t there a massive redesign in the aftermath of that?

yep. It was called the Pro2 Evo.

Posted by: bens

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Is this a common thing? I've broken a lot of stuff over the years but never the axle.

I've bust a Pro2 Evo before, on an XC hardtail. 

I have a hard-charging mate that rides hardtails who's had steel axles made for his bikes as he's broken a few axles. Problem solved, apparently.

Stans Neo by any chance?

I did the same on a Stans Neo hub - replaced the axle with a stainless steel one and it's been (fingers crossed!) ok since.

How? I don't know the answer but it happened to me a couple of months ago. I was removing the maxle and could feel the cassette wobble so I tightened it up and went for another Lakeland ride. When I got home and removed the maxle the freehub and cassette fell off. It was replaced under warranty.

Have never snapped an inner axle or heard of anyone doint it apart from one mate who's snapped the inner axle on an American Industries hub twice in the space of 3 years. 

Did it on an old hope pro 2 but they are quite well known for it and it is very thin in the middle. No joy from hope but replacements were available elsewhere.

I suspect yours is a mix of poor design and impacts. I'd replace it and if it happens again look at a different hub.

Happened to me on a hunt rear wheel.  I lost the little red spacer that separated the bearings so bearing outer was rubbing on bearing outer. I can only presume this generated a lot of heat which made the axle brittle and it snapped.  My guess not fact. 

I've snapped two in the past. Both times it was in the same Superstar rear hub that I think is a rebadged Corratec, although I might be wrong.

I think the alloy axles were just poor parts, to be honest. The problem was solved with a steel axle that Corratec(?) also marketed. The hub itself wasn't very good - it ended with one of the double-flap type pawls wriggling around, getting stuck and carving a groove down the middle of the ratchet teeth. It was a bin job after that.

I used to routinely break QR axles when trials riding. I think Hunt rear hubs were known for snapping axles on early versions but they redesigned things to fix it. 

Cheers everyone.

Hunt have said they offer a steel version but it's not available via their website so just waiting to hear back on how to actually buy one.

To be fair, the original alloy one lasted fine for maybe 2k miles so I'd be happy with another alloy one (which are available via their website).

I did wonder whether I could use this as an excuse for some nicer wheels but £12  for a replacement vs £xxx for new wheels is a hard one to justify to myself.