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  1. #1
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    Shimano XT 142x12 rear hub toast after 500km

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    After approx 500km on the Shimano XT 788 rearhub it started to make loud grinding noises when pedalling and at other times when freewheeling.Yesterday it also seized completely turning bike into a 2x9 Fixie.Managed to "break" it loose again and made it home.
    Took cassette off and freehubbody shell was split in 4 !
    uploaded some pics here

    https://picasaweb.google.com/casparbc/788Freilauf

    Anybody else have this bad luck with xt,xtr or saint 12mm hubs ? is this the ISIS of 12mm hubs, or was I just unlucky ?

    Cheers Caspar

  2. #2
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    Screams Warranty to me!!!!! never seen it before.

  3. #3
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    I thought I read somewhere that Shimano products get their best performance in miles and weren't really meant for riding in km's. I suspect that's what's going on here.

  4. #4
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    A friend of mine wanted to take the bumper off his truck he brought me a 1 1/4 socket which I put on my 3/8 drive Sears craftsman socket wrench. All four nuts were seized so all 4 bolts broke. The craftsman was not damaged. Shimano does not know how to make a ratchet keep returning them until they figure it out.

  5. #5
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    Wow, that's a bummer. I have the same XT 788 12x142 hub, and I've put over 2000 miles (3200 km) on it without any trouble or maintenance. I ride/race XC, and I only weigh 155 lbs (70 kg) so I am not the type of rider to break many hubs. This hub is designed for XC use, so if you are a very aggressive rider you may want to buy a stronger hub. Otherwise, if you replace the free hub you will probably be fine in the future.

  6. #6
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    Blew it again !

    Blew the second freehub tdy , what a piece of c... this 788 hub.
    Aprox same amount of riding time on the second freehub and there she blow !
    Been on Xt hubs for some 20+ yrs , cant belive Shimano could make such a lemon.


    Obviously freehub is undersized , theres some tiny steel balls in there to make room for the 12mm axel.
    No more Shimano rearhubs for me EVER !
    Luckily I got the 12x142 axelkit for my hadley rearhub last week , time for a new wheelbuild !

  7. #7
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    Quote Originally Posted by caspar View Post
    Blew the second freehub tdy , what a piece of c... this 788 hub.
    Aprox same amount of riding time on the second freehub and there she blow !
    Been on Xt hubs for some 20+ yrs , cant belive Shimano could make such a lemon.


    Obviously freehub is undersized , theres some tiny steel balls in there to make room for the 12mm axel.
    No more Shimano rearhubs for me EVER !
    Luckily I got the 12x142 axelkit for my hadley rearhub last week , time for a new wheelbuild !
    Sadly the XT hubs have been a disaster the last few years...but the SLX ones are rock solid with Cro-Mo axles and heavy duty 32poe freehub bodies.

    Universal Cycles -- Shimano HB-M678 SLX Centerlock Rear Hub - 2013

  8. #8
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    Quote Originally Posted by mtnbiker72 View Post
    Sadly the XT hubs have been a disaster the last few years...but the SLX ones are rock solid with Cro-Mo axles and heavy duty 32poe freehub bodies.

    Universal Cycles -- Shimano HB-M678 SLX Centerlock Rear Hub - 2013
    Doubt very much SLX will be any different . My guess is only diff btwn XT and SLX is alloy vs steel axel , to meet diff. pricepoint. Hubshell and freehub is prob. the same , and freehub shell cant be any beefier as it still has to make room for the hollow 12mm axel.and pawls and ratcheing mech. inside freehubbody.

    Maybe XTR will hold up as freehub shell is Titanium.....?
    I dont know and will not spend money to find out , from now on its Hadley for me

    Cheers

  9. #9
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    I've had the EXACT same thing happen to me with an SLX hub.

    The M678 hub had maybe 5 rides on it when it exploded. It seized up (luckily near the start of a ride) into a fixed hub, sending my chain into the crankset when I coasted. When a bike shop mechanic removed the cassette, the freehub shell fell onto the shop floor in 4 or 5 fragments. The fragments look just like Caspar's.

    The hub was warrantied, but not until after I had bought a new rear wheel to get me rolling again (I was in a pinch, and now I'm out $250). Hopefully this won't happen again with the replacement freehub. Not very reassuring though.

  10. #10
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    That is a bummer. I am a fan of Shimano. I hope I got a good one. I have XTR 988, and would imagine that Titanium is much weaker than stainless steel. My single speed Chris King is flawless (stainless drive shell). I WILL sell XTR set at first breakage/warranty freehub. Maybe I will stick with made in USA from now on. Always wanted White Industries.

  11. #11
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    As per this new thread I posted, am wondering what the current situation is with Shimano 142x12 hubs?
    Are some models of the current Shimano hubs (Deore, SLX, XT etc) considered more/less problematic than others?
    Thanks...

  12. #12
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    Yep, I had exactly the same thing after ~800km. Only freehub shell on mine was split in two, like a walnut. I bought the wheel from Wiggle.com, and they just refunded me. A pity, as I liked the wheel, the UST and how stiff it was. Got SLX version instead, and while cheaper, it is not quite the same. And After many freehub failures, I do not expect them to last - just consider yourself lucky if it happens inside the warranty period :-)

  13. #13
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    To update, I had the issue happen a SECOND time, on the warrantied/replacement hub.
    Again, the SLX M678 freehub shell cracked and fragmented.

    CRC once again replaced the hub without hassle. But I'm on the fence about about rebuilding the wheel.. the hub exploding seems a matter of when rather than if.

    Photos from the 1st time:
    Shimano XT 142x12 rear hub toast after 500km-img_5776s.jpgShimano XT 142x12 rear hub toast after 500km-img_5782s.jpg

    and the 2nd time:
    Shimano XT 142x12 rear hub toast after 500km-img_20140329_145029s.jpg

  14. #14
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    Jra?
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  15. #15
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    Quote Originally Posted by car bone View Post
    Jra?
    That's cute.

    I ride a trail bike on, well, trails. I'm not the smoothest or lightest rider, but I'm not taking it to any DH parks either. I'd say pretty typical stuff for anyone who identifies themselves somewhere in the XC to AM range.

  16. #16
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    welcome to the club. there are a couple treads going on the quality of the 788. after the pain of replacing, waiting and wondering if another was gonna blow i saved up some clams and made ordered a chris king hub.

  17. #17
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    Get it fixed and sell it, if the SLX isn't going to hold up then nothing from Shimano will. I'd step up to a DT or White Industries for a new centerlock hub.

  18. #18
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    Shimano XT 142x12 rear hub toast after 500km

    So this problem affects SLX and XT hubs? Basically there are no known Shimano hubs that DONT have this issue? Can that be right? Thanks...

  19. #19
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    I have not had this issue, but I'm 70kg. and never used the xt only slx 9mm qr.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  20. #20
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    Did this on two XT wheels in the last two years, one with only ~30 mi. on it.

    According to Shimano, they had a very large batch of bad freehub shells, (the freehub I cracked this year was NOS) and if replaced on warranty, they shouldn't crack again. I replaced one about halfway through the summer last year, and it stayed intact, and the one I replaced this year is okay so far. Riding pretty rowdy on an SB-66.

    Its pretty easy to keep an eye out for, I.E., identify before it seizes up. If your cassette is wiggling, its broken. Keep an ear on your shifting too.

  21. #21
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    I went through two of these in a year. They warranted one of them. I put a thousand miles on that bike in a year, but I dont think I should need to go through two of them. And to make it even more of a pain in the ass, the availability of replacement freehub bodies was NOT good. Had to wait weeks the second time.

  22. #22
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    Re: Shimano XT 142x12 rear hub toast after 500km

    Quote Originally Posted by ZomblibulaX View Post

    Its pretty easy to keep an eye out for, I.E., identify before it seizes up. If your cassette is wiggling, its broken. Keep an ear on your shifting too.
    Damn!!!, found my cassette wiggling on Sunday, new XT hub with only ~500kms, its currently at lbs, ld feared this may happen, lm 95kgs
    always mad and usually drunk......

  23. #23
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    I was expecting a fight, but my lbs said they know of the problem, and that its a warranty replacement that has been done and to come and pick it up

    Then I asked "what if it happens again?", and was assured that Shimano have rectified the issue and I should be ok. If not then I go back again and I go to something else a little better............ will have to wait and see
    always mad and usually drunk......

  24. #24
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    Had the same kind of issue with my SLX freehub see picture :

    http://i60.tinypic.com/2wndbnt.jpg

    The LBS sent the Wheel to Rocky Mountain, which replaced the freehub a couple weeks ago.

    But yesterday, I removed my cassette and I feel like the freehub is not turning freely as it should, like its grinding inside.

  25. #25
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    Remove the freehub from the hub and dunk it in white spirit (and let soak), dry it out (with perhaps acetone) then dunk it in oil.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  26. #26
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    Quote Originally Posted by cmg71 View Post
    Then I asked "what if it happens again?", and was assured that Shimano have rectified the issue and I should be ok.
    I have had the freehub shell disintegrate on my second warranty replacement. That's right, it has happened to three SLX M678 hubs. This last time, the smallest cog of the cassette sheared off the end of the freehub shell, while the rest of the shell cracked into a handful of fragments. If anyone is interested I have photos from all three failures.

    This may have been mentioned, but seems to me like the the steel shell may have been made too thin in order to accommodate the 12mm thru-axle. I suppose you get what you pay for. Not even worth lacing up if the hub is free, unless you love downtime from the bike.

  27. #27
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    Quote Originally Posted by car bone View Post
    Remove the freehub from the hub and dunk it in white spirit (and let soak), dry it out (with perhaps acetone) then dunk it in oil.
    I would suggest removing hub from wheel and dunking it in the trash.

  28. #28
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    Something didn't feel right about the drivetrain and it seemed like the cassette was too wobbly. I cleaned my freehub and cassette and noticed what looked like a crack. Stuck my fingernail in it and a huge chunk of the freehub body fell off.

    I called Shimano today and they said there was an issue with this on the early freehubs for the M788. They will warranty it, but it's easier to do it through your bike shop if possible. However, from the looks of this and other threads, it looks like the replacements aren't fairing any better. I bought a cheap set of Mavic Crossrides as a backup wheel set so I can still ride while a I wait for this to get solved.

    You can call them at:
    Shimano American Corp.
    (800) 423-2420


  29. #29
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    I discovered this thread after searching for the solution to my problem with my weird sound. It looks as though the freehub is the cause. My rear hub is an SLX M678 from a 2014 Scott Genius 730. Bike tech said he took apart the hub and lubed everything but when I spin the back and clock the pedals at different angles a grinding/rubbing sound eminates from the rear.

  30. #30
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    Just a note for future reference or anyone finding this via Google. On further inspection my M678 freehub also has a fracture. The freehub can be warrantied as previously mentioned. However, the entire hub assembly itself is cheaper to buy (and the freehub is mostly sold out everywhere). I plan to use the internals from the new hub to service my current mounted one later.

    The M788 and M828 all share the same freehub so don't think it will be any different going to a higher XT freehub unless you want to drop $200 on the titanium freehub.

  31. #31
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    Quote Originally Posted by Jman0000 View Post
    Something didn't feel right about the drivetrain and it seemed like the cassette was too wobbly. I cleaned my freehub and cassette and noticed what looked like a crack. Stuck my fingernail in it and a huge chunk of the freehub body fell off.

    I called Shimano today and they said there was an issue with this on the early freehubs for the M788. They will warranty it, but it's easier to do it through your bike shop if possible. However, from the looks of this and other threads, it looks like the replacements aren't fairing any better. I bought a cheap set of Mavic Crossrides as a backup wheel set so I can still ride while a I wait for this to get solved.

    You can call them at:
    Shimano American Corp.
    (800) 423-2420

    No wonder the freehub felt wobbly, your whole freehub is cracked. and its actually in at least 2 pieces.

    Your mavics will suck like 100 times as much trust me.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  32. #32
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    I recommend true precision stealth hubs. I have over 10000km on my rear, haven't done jack chit. get those if you can, and then use some really sticky (industrial) grease outside the main big bearing next to the cassette, waterproofing the whole crap. 10k man.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  33. #33
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    Quote Originally Posted by elementsix View Post
    Just a note for future reference or anyone finding this via Google. On further inspection my M678 freehub also has a fracture. The freehub can be warrantied as previously mentioned. However, the entire hub assembly itself is cheaper to buy (and the freehub is mostly sold out everywhere). I plan to use the internals from the new hub to service my current mounted one later.

    The M788 and M828 all share the same freehub so don't think it will be any different going to a higher XT freehub unless you want to drop $200 on the titanium freehub.
    Yeah man thats the tradeoff. either you make sh1t hard and strong but brittle or you make them soft/weak but ductile. and in the shimano case they have the actual mech inside the god damn freehub to save whatever. and for some people it works out, for some it doesn't. yeah go figure. the flaw seems to be with shimano putting the rachet in the freehub part. I wish they put it inside the hub part instead.

    The shimanos have long pawl engagement areas though, like 5x longer/5x more metal than any competitor.

    I would just get the whole hub and strip it for parts. cheapest way.

    That being said I'm putting 2 slx rfear hubs on my new lynskey. Since I only weigh 70kg and i know these have worked well for me in the past. Hell even the really cheap chitty ones last for ages for me. And they don't even have seals at all!!

    don't get a 200 bux freehub! are you fuking crazy.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

    Quote Originally Posted by iheartbicycles View Post
    Specialized sucks ass.

  34. #34
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    Quote Originally Posted by car bone View Post
    No wonder the freehub felt wobbly, your whole freehub is cracked. and its actually in at least 2 pieces.

    Your mavics will suck like 100 times as much trust me.
    Well, duh, car bone. That was the point of why it felt wobbly. Actually, it's pretty surprising how well the cassette was holding things together, that is, until I removed it and started cleaning everything.

    By the way, I know the Cross-Rides aren't a great wheel-set. I simply bought them as a back-up set to get me through the warranty lag of this free hub body from Shimano, plus they'll serve to get me through any other disasters than can happen from time to time (i.e. broken spokes, bent rims, other hub problems, etc...). I'll just keep 'em in the truck when I go ride and I can keep riding if one of the wheels gets damaged due to some accident or another component failure. I am, by no means, counting on them as being my everyday set. I know they won't last... I will say this though, they are surprisingly stiff for their price and weight, but I can tell the bearings won't last very long. At only $300, if I rode them for only year before they broke, I'd be happy. I can't imagine them holding up longer than that, but again, I'm not planning to use them that way. They're just to keep me rolling when disaster strikes...

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