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Rear hub ball bearings - how many?

Inverted8Inverted8 Posts: 48
edited May 2009 in MTB workshop & tech
I just serviced my rear Shimano hub for the 1st time due to excessive play on the rear axle. I've had the bike (2008 Stumpjumper Comp) from new for about a year now. I found that there were only about 5 ball bearings either side of the hub (total about 10), although 1 or 2 may have droppped out whilst dismantling. Is this normal? I ended up replacing them with 9 bearings either side. The wheel now runs smooth and no play at all. Will running so few bearings in the hub wear out the cones prematurely? I cannot believe that so few ball bearings were in there originally.

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  • Chaz.HardingChaz.Harding Posts: 3,144
    I think you've just answered you own question.

    If they fit, and the wheel spins smoothly, then no problem.

    And yes, the less bearings you have, the more pressure they each exert, so wearing the cones (and themselves) faster :wink:
    Boo-yah mofo
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  • nicklousenicklouse Posts: 81,520 Lives Here
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • elPedro666elPedro666 Posts: 1,060
    Inverted8 wrote:
    I found that there were only about 5 ball bearings either side of the hub (total about 10), although 1 or 2 may have droppped out whilst dismantling. Is this normal?

    Have you looked under the fridge? You'll find eight ball bearings under there, unless they've already passed into Narnia & been melted down to form sword blades for mythical Centaurs.
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  • Monty888Monty888 Posts: 44
    I've just serviced a Shimano MTB rear hub too - 2002 vintage from a Specialized Hardrock. All bearings were accounted for when the axle came out - no fridges, no bearings rolling across the floor or anything like that. There were indeed only five on each side. Very weird.
  • nicklousenicklouse Posts: 81,520 Lives Here
    Monty888
    Not right and very strange.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • allthegearnoideaallthegearnoidea Posts: 4,077
    i used to dismantle my old wheels over a magnetic tray! that way any that fell out would land in the trays!
    i only learnt this after doing it out side before and having to use said trays to sweep the floor to find the little b#ggers! :D
    Timmo.
    After all, I am Cornish!
    http://cornwallmtb.kk5.org/
    Cotic Soul, The bike of Legends!:wink: Yes, I Am a bike tart!
    http://www.bikeradar.com/forums/viewtop ... 1#16297481
  • Monty888Monty888 Posts: 44
    Twas a Shimano hub made in Malaysia, so maybe not up to Japanese standards. :-)

    Hard to believe I've done so much riding on that hub with only five bearings on each side. The amount of empty space in the cups is substantial.
  • Inverted8Inverted8 Posts: 48
    I am 99.999% certain that no bearings droppped out and gobbled up by the Big Bad Bearing Monster! I think that with reduced amount of bearings in the first place induced excessive wear and hence play in the axle. Maybe it is a Friday afternoon hub! I'm tempted to diassemble my other bike to check - also Shimano.
  • Dave LoasbyDave Loasby Posts: 32
    i need to do mine soon so i will see how many my deores have.
    Former employee of Ray Inkley cycles 1989-1991

    ex Lincoln Wheelers 1981-1990 iirc. TT + U12 CX
  • Monty888Monty888 Posts: 44
    I take it all back. Malaysians know how to count ball bearings.

    When I looked at the rear wheel in daylight today, I could see empty space inside the body of the hub. There's lots of room in there - much more than the space necessary to accommodate the axle. I flushed it through with degreaser and the missing eight bearings eventually dropped out.

    So, Inverted8, maybe your AWOL bearings are stuck inside the hub as well. Your wheel's going to sound like a rattle when the grease dries out. :-P
  • supersonicsupersonic Posts: 82,708 Lives Here
    They often fall into the hub body when you take the axle out. Then the grease makes them stick!
  • allthegearnoideaallthegearnoidea Posts: 4,077
    a small magnetic telescopic tool is greta for pulling the bearings out the hub! can be had for a couple of quid from the local motor factors too!
    very handy for getting all the balls out in one go!
    Timmo.
    After all, I am Cornish!
    http://cornwallmtb.kk5.org/
    Cotic Soul, The bike of Legends!:wink: Yes, I Am a bike tart!
    http://www.bikeradar.com/forums/viewtop ... 1#16297481
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