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It isn’t and therefore there shouldn’t be any play
I must be imagining it then.
As mentioned above, the Cycling UK forum loves this topic.
Cup and cone bearings are good. You can maintain them easily and all you need is grease and a rag and a few simple tools.
I think QR Shimano hubs are brilliant. Tough flanges and big bearings in the right place. I am not sure about through axle ones as I don’t have any Shimano through axle hubs. Generally, as axle sizes increase bearing sizes decrease which I don’t like.
And the thing about setting cones so they are slightly loose is true. Stick them in the frame, tighten the QR and the play is taken up. People say it’s the axle compressing. I wonder if it the axle bending slightly. Whatever it is, the system works.
I think QR Shimano hubs are brilliant.
Admittedly, I only got 20 years out of my last set.
I’m not saying that you have to do the loose then tight thing. It may help but then again many don’t do it with no problems.
When I say it’s true, I mean it’s true that slight play will usually be taken up when you tighten the qr.
@oceanskipper you say you don't know about c+c hubs and yet you know enough to say this?
Next time I take my wheel to bits I’ll try it but trying to determine if any play is taken up will be tricky me thinks…
Adjust a bit of play into the hub, put it in the frame, feel the play, tightener the qr, see that happens.
well I’ve only taken a wheel apart once ( well it ended up being about 5 times as I did them up obviously too tight the first time and too loose the second and third!) so clearly that won’t make me an expert in c+c, hence the start of the thread. I have done a lot of reading since then though. 👍
EDIT I did think I had left the teeniest, tiniest amount of play I at one point but it did not disappear, whether it was reduced or not I couldn’t tell but I don’t think I could have made much of a finer adjustment on the cone to retest under the exact same conditions.
I had assumed that the force developed by a QR skewer/lever wouldn’t be enough to compress the axle (moreover, by more than the skewer itself stretches) an appreciable amount
I've just tried to work this out. (Disclaimer - I am not an engineer.)
Young's modulus specifies how much the axle will compress - dL = F x L0 / A x E.
Force F = 3000 N (from the Peak Torque video linked to above)
Axle length L0 = 130mm
Axle area A... I think a QR axle is a 10mm axle with a 7mm hole for the skewer - so A = Pi * ((0.005)^2 - (0.0035)^2) = 4 x 10-5 m
Young's modulus E = 200 GPa (from Wikipedia)
So change in length dl = 3000 N * 130 mm / (0.00004 m2 * 200,000,000,000 N/m2) = 0.05 mm
The thread pitch on the axle is perhaps 1mm so that's 1/20th of a turn.
That's in the right ballpark - it's too low by about a factor of 3 on the observed effect but I've likely got some of the numbers wrong. So I'd say this is inconclusive on proving or disproving axle compression as the cause.
I think that's actually pretty close to the observed effect IME, somewhere in the region of tenths of a turn?
A good recent thread that also links to many of the other relevant past discussions at the cycling UK forum. https://forum.cyclinguk.org/viewtopic.php?f=5&t=143125
I've always thought it wasn't the axle compressing, but the threads flexing, being as they are perpendicular to the force you're applying when you tighten down on the lock nut, and transferring that force to the axle.
you get used to how much play to leave, depending on how much the lock nut grabs the axle and turns the whole lot when you tighten, essentially loosening the cone off a bit. I'm so used to it that I had to re-learn a bit when I first used an axle vice.
XT hubs are a bit different though. adjust the same, but different as you can't really see the axle turning when you tighten the locknut, as it threads over the end of the larger diameter alu axle (for the QR version).
Right - 1/10 of a turn sounds like a good starting point and gives a really good insight into the kind of tolerances we are talking about. Thanks.