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I recently bought a 2012 Santa Cruz Superlight 29, and there is some play in the rear wheel. The hub is an FH-M975 (XTR). With the wheel off, you can tell there's some play, but I guess there is supposed to be a little to begin with, and tightening the quick-release should remove the play. Even with a very tight quick-release, there is still noticeable play.

So, I decided to overhaul the hub following the instructions in Zinn. The overhaul went well, but the only way to get the play out is to really crank down the cone so there is no perceivable play in the axle. Zinn is clear, and other advice says the same, to make sure there is some play in the axle, then the quick-release will tighten it up. That said, I have it pretty tight now, and there is only just barely perceivable play in the wheel, and it spins just fine as far as I can tell.

Is there anything wrong here? Could something else be causing this problem? Should I just crank it down a little more until there is no play in the wheel?

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  • This can get futzy. Sometimes you need to leave a fair amount of play before the skewer takes over, other times almost none. Depends on the bits in the hub, I suspect.
    – Daniel R Hicks
    May 29, 2020 at 1:14
  • thanks Daniel. i'm confused about how to feel for friction. the freehub moves (clicks) freely, but the axle does not move by hand in the other direction. is that right? or should it move freely?
    – tef2128
    May 29, 2020 at 1:48
  • You should be able to grasp the axle and twist it inside the hub body.
    – Daniel R Hicks
    May 29, 2020 at 1:51
  • Really cranking down the cone destroys the bearings and locks the axle in place. For a 8 year old bike it's not out of question that the bearing would be just worn enough that they can't be adjusted to perfection any more. Replacement bearing balls are cheap and even cones aren't that expensive if you want to try replacing them.
    – ojs
    May 29, 2020 at 10:06
  • @ojs One of the cones on this is integral to the axle and the unit is probably unobtainium, and they're expensive when they are available.
    – Nathan Knutson
    May 29, 2020 at 15:28

2 Answers 2

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The advice that there should be play in a QR hub before tightening the skewer is true for a very high percent of QR bikes in the world because they have standard M10 or 3/8" steel axles, which flex under the load applied by the QR.

Many higher end hubs have oversize axles, usually aluminum, that see little or none of this flex and need to be adjusted as such if they're adjustable. FH-M975 is certainly in this camp, as are a lot of Shimano's higher end hubs from the last decade.

A good test whenever there's uncertainty is to adjust it so there's the smallest perceptible bit of play and observe what happens as you close the QR lever down. It's moving 180­° and it should start hitting resistance at 90°. What you want in an axle that does flex is for there to be play remaining at the 45° point but for it all to be taken up in the last 45° of movement, or the last quarter of its total movement. That will give you an essentially perfect adjustment on any QR hub and is also a test for whether the axle stiffness is such that it gets compressed meaningfully from QR forces. In other words, if you find that the play is unchanged from QR compression, you should then go back and adjust it so that all play is removed off the bike.

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If the axle is still loose when the QR is tightened, then you need to tighten the axle a bit more.

If the wheel doesn't spin freely when the QR is tightened, you need to tighten the axle a bit less.

It's fiddly but it's as simple as that. Try adjusting the axle just untill there is no play in the bearings, then try again.

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