SLX M678 Freehub failure

[kwikee]

Quick ride with the kids tonight and I noticed what seemed to be a 'clicking' in the pedal, then could've been the bottom bracket. Or the other pedal? Got back home and put it on the stand to have a closer inspection and noticed some rubbing noise like brake rub but from the cassette at low wheel rpm.
I pushed on the cassette and it was noticeably loose on the hub. Took it off and a piece of the freehub thread came off, and there are two cracks through the freehub body.

This bike is less than 6 months old (2 months with me), and while I can't vouch for previous use, I have done about 500k's on it. I'd have thought a freehub should be good for several thousand km's? What might cause this failure? I haven't removed the cassette on this bike prior to tonight so not sure of the torque it was fitted at. Seemed easy to undo, but the thread had failed as well as the cracking so couldn't hold too tight.
Anyway, I'm wondering if there are any options other than another SLX body that I could get? Would an XT freehub fit? And if it does, is it actually different?
A freehub is about $50-60, whereas a whole rear hub is about $75. I've read up a bit and There seems to be some evidence of early failures of this part. Should I maybe consider another hub?



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[ChopSticks]

can you see where the crack is starting/propagating from?
Ie from lockring in towards the centre of hub? or from center out towards lockring? (looks cracked through and through?)

if its starting from the lock ring, then I'd guess the factory/previous owner/lbs cranked the lockring on too tight, you put the power down in the highest gear (smallest ring on cassette) and sheared it off?

any chance you can ask for warranty through the previous owner?

how much are you willing to spend? and what are your skills... ie will you be comfortable replacing a free hub? or replacing/relacing a new hub? or will you take it to a LBS to get it done regardless?

might also be worth while upgrading your entire wheelset during this pickle.....?

 

[kwikee]

can you see where the crack is starting/propagating from?
Ie from lockring in towards the centre of hub? or from center out towards lockring? (looks cracked through and through?)

Judging from the broken thread, I'm guessing it's started from there, but very hard to determine.

if its starting from the lock ring, then I'd guess the factory/previous owner/lbs cranked the lockring on too tight, you put the power down in the highest gear (smallest ring on cassette) and sheared it off?

any chance you can ask for warranty through the previous owner?

Possibly. For what it's worth, though, I don't know that I'd bother with the delay.

how much are you willing to spend? and what are your skills... ie will you be comfortable replacing a free hub? or replacing/relacing a new hub? or will you take it to a LBS to get it done regardless?

$85-100 will get a new, complete hub posted so thereabouts. I'm more than comfortable to replace the freehub, I'd even consider having a go at rebuilding the wheel with a new hub.

might also be worth while upgrading your entire wheelset during this pickle.....?

Perhaps. Although given I've just outlayed for the bike, that may not be on the cards just yet.

All in all, I quite like these wheels despite my initial reservations, so building a new hub in could be a good option. Always keen to learn a new skill and that would alleviate any issues, proven or otherwise, with Shimano's recent freehubs. Hope hubs seems to get great raps, a bit pricey but reliability and longevity are both important to me. Don't mind paying a bit more if it's genuinely worth it.



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[ChopSticks]

All in all, I quite like these wheels despite my initial reservations, so building a new hub in could be a good option. Always keen to learn a new skill and that would alleviate any issues, proven or otherwise, with Shimano's recent freehubs. Hope hubs seems to get great raps, a bit pricey but reliability and longevity are both important to me. Don't mind paying a bit more if it's genuinely worth it.

so assuming you get an XT hub, replace it and learn a new skill in the process...that would be great stuff !

but if you end up sourcing a new hub to something that has more bling and more PoE (ie Hope) bare in mind the cost of a stand alone hub vs a hope hoop.... usually not much in it if you add the cost of a hub and rim... you prob get the spokes and the build free. so keep that in mind !

 

[Rutter]

This happens to all 142x12 slx/xt free hubs have seen heaps of them do this. Even the replacements you get do the same. My mate has gone through 3 in about a two months, ended up buying new wheels......

 

[outtacontrol]

I bet it's a 29ner?

Have seen this with XT hubs. Shimano have new model that they tout as a 29ner specific. The theory seems to be that the bigger wheel creates more torque on the hub?

Beyond me, but I have had this debate with someone else awhile ago and found the new hub that states it's designed for the bigger wheel. Could be marketing hype, but then this seems to keep happening??

 

[kwikee]

I bet it's a 29ner?

Have seen this with XT hubs. Shimano have new model that they tout as a 29ner specific. The theory seems to be that the bigger wheel creates more torque on the hub?

Beyond me, but I have had this debate with someone else awhile ago and found the new hub that states it's designed for the bigger wheel. Could be marketing hype, but then this seems to keep happening??

27.5". Do you know the model number?
Seems to be the 142x12 that has the problems.


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[kwikee]

Ended up finding a new freehub for $45 so bought that. I'll be particular about how tight it is, and keep a close eye on it because I don't get the feeling it's going to last a long time. If that gets me through to Summer, I might have some funds available for a new wheelset.


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[Daniel Bordeleau]

You may want to take a look at this thread :

http://forums.mtbr.com/wheels-tires/shimano-xt-142x12-rear-hub-toast-after-500km-791039.html

Same thing happened to me on my 2014 RM Altitude 750. Had it fixed under warranty

Dan

 

[Shadow Puppet]

This happened to four of my mates. All riding 26ers, all on XT Freehubs. 1 mate had it happen three times, they kept replacing it and in the end just sent him an XTR one.

Saying that, I've been on an XT wheelset for 2 1/2 years and replaced the freehub once with normal wear and tear.

I recon the one that has cracked on you could be from the bad batch they had about a year ago and the new ones most likely have been fixed.

 

[kwikee]

I'm hoping. I've since fitted a new one, no idea how old it is or from what batch! The same freehub is used from Deore, through Zee to XT and it seems only the 12mm TA are affected.
It just needs to get me to summer, then I'll get a set if Arch EX on Hope Pro 2's and that should be the end if my troubles.


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[Shadow Puppet]

I'm hoping. I've since fitted a new one, no idea how old it is or from what batch! The same freehub is used from Deore, through Zee to XT and it seems only the 12mm TA are affected.
It just needs to get me to summer, then I'll get a set if Arch EX on Hope Pro 2's and that should be the end if my troubles.


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The cases I know of were the regular QR hubs not 12mm through axle.

 

[kwikee]

The cases I know of were the regular QR hubs not 12mm through axle.

Ok, general consensus from what I've read is the 12mm has too thin a sidewall to the casting to allow for the 12mm axle, and the QR is thick enough and not a problem.
Of it's also QR, then the batch issue sounds plausible. Otherwise, it appears to be a design fault that Shimano won't recognise.
Either way, the logical part of me thinks that when people talk of a Shimano "freehub issue", is it really, or is it simply that Shimano gear is spec'ed on so many new bikes and that purely due to market share, their rate of failure in quantity should indeed be higher, however that rate as a percentage of units sold may well be equal to or less than the minor brands. Sound plausible? Or have Shimano got a problem?
I'll bet there are HEAPS of riders who are using Deore/SLX/XT hubs with no issues...

 

[redbruce]

Quick ride with the kids tonight and I noticed what seemed to be a 'clicking' in the pedal, then could've been the bottom bracket. Or the other pedal? Got back home and put it on the stand to have a closer inspection and noticed some rubbing noise like brake rub but from the cassette at low wheel rpm.
I pushed on the cassette and it was noticeably loose on the hub. Took it off and a piece of the freehub thread came off, and there are two cracks through the freehub body.

This bike is less than 6 months old (2 months with me), and while I can't vouch for previous use, I have done about 500k's on it. I'd have thought a freehub should be good for several thousand km's? What might cause this failure? I haven't removed the cassette on this bike prior to tonight so not sure of the torque it was fitted at. Seemed easy to undo, but the thread had failed as well as the cracking so couldn't hold too tight.
Anyway, I'm wondering if there are any options other than another SLX body that I could get? Would an XT freehub fit? And if it does, is it actually different?
A freehub is about $50-60, whereas a whole rear hub is about $75. I've read up a bit and There seems to be some evidence of early failures of this part. Should I maybe consider another hub?

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Two separate modes of failure here.

Bit hard to tell where the cracks along the freehub started but looks to have started at the hub end(where the pawls load it radially).

The thread end fault appears independent of the two lateral freehub cracks and looks like either the freehub is too thin in the thread area or the locknut was too tight.

Given both issues I suspect Shimano have reduced material a bit too much.

If its a common problem with SLX and XT I would put a steel freehub on if available.

It just needs to get me to summer, then I'll get a set if Arch EX on Hope Pro 2's and that should be the end if my troubles.

Hope are pretty good but not perfect.

http://forums.mtbr.com/wheels-tires/hope-pro-ii-freehub-problems-736617.html

Have had two mates with same issue.

 

[The Duckmeister]

..... I would put a steel freehub on if available.

It is a steel freehub. Dura-Ace & XTR (both titanium) are the only non-steel freehubs in the Shimano arsenal. Aluminium was used briefly on early road 10-sp, but phased out probably six or so years ago, and never used on MTB hubs.

 

[empee]

I am told that Shimano's new stock has been updated to resolve this issue...