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rear XT hub M775 bearing failure

craighudsoncraighudson Posts: 64
edited May 2010 in MTB workshop & tech
I have Shimano XT wheels on my Merida 96 3000D bike. Unfortunately the bike is only a year old and the following problem has happened twice already! The Problem is that the bearings on the drive side keep on coming loose and destroying the axle. Thankfully I caught it this time. I took the freewheel/cassette of to give the bearings a service only to find 13 of them all bunched over on one side. According to the Shimano Tech sheet there should be 20 in there. As it was my LBS that built it after the last time I had imagined that they would have built it correctly using the right amount of BB and the right size. can anyone confirm the actual right amount and size of BB in the rear M775 XT hub please.


  • supersonicsupersonic Posts: 82,708 Lives Here
    Usually are 9 a side, quarter inch.

    Are you sure you have not dropped them into the hub body?

    If they have rebuilt them wrong, they owe you.
  • craighudsoncraighudson Posts: 64
    Cheers for that, it certainly looks like there should bigger bearing than the 3/16 bearings in there at the moment. No I did not drop any through the other side, I was exceptionally carefull to avoid any possibility of that. All the bearings were all crammed into one of the drive side. I just ordered some 3/16 ones from Ebay although it only cost me 2.50 for 125 of them. I will try and get some 1/4" ones tomorrow. cheers
  • supersonicsupersonic Posts: 82,708 Lives Here
    Just checked with Shimano is an odd ball.

    They are 3/16, 10 a side. Very strange.
  • craighudsoncraighudson Posts: 64
    Yes this is slightly weird i agree. I am going down the LBS this afternoon to check with them, I will post the reply tonight.
  • nicklousenicklouse Posts: 50,675 Lives Here
    they should have been caged as well.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • craighudsoncraighudson Posts: 64
    Went back to the shop today, the end section of the bearing the hub axle unit that the bearings sit against when it is screwed in has been slightly damaged, not bad just a little pitted so will now be on the hunt for a new hub axle unit or a new rear hope hub if I can find one cheap enough. any suggestions for good reliable relativaly cheap rear hubs that will last with out having to strip them every week in life.
    I have Mavic Crossmax SLR on the other bike and they have been superb for the last 3 years without them having to be removed and stripped once.
  • lesz42lesz42 Posts: 690
    i have the 775 hubs, the rear has issues, with nuts, undoing, if not done up VERY tight, and dirt entering the drive side

    mine only has a cage on the drive side, and a new axle is about £25, mine are a tiny bit pitted, just changed the bearings, might get the wheel rebuilt, with the same new hub for £60 all in.
    Giant Trance X0 (08) Reverb, Hope Hoops 5.1D, XT brakes, RQ BC, Works Components headset 1.5
  • craighudsoncraighudson Posts: 64
    It is the drive side that I am always having trouble with. The shop has just rebuilt the hubs with new grease etc so I hope they should be clear for a few months now that winter is clear. I will not be aiming to keep XT hubs on this bike though.
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