Anybody know what might be going on here...?
When tightening the QR on my the rear wheel, the rear mech moves inward slightly and there is some resistance when spinning the wheel. Not enough to stop it, but as if the brakes are slightly rubbing. When I release the QR then it spins freely.
Tried different wheels and QRs with same effect. I can't see anything which may be causing rubbing...
Is your mech hanger loose?
Worn freewheel bearings?
Are you over tightening the qr? If there is nothing rubbing and you've tried other wheels then you prossibly are. What wheels are they?
This could be nonsense but: could it be that you're pulling the chain stays together and the rubber seal on the wheel is rubbing against them?? I've had similar before and that is what appeared to be happening to me. (Apologies if terms somewhat incorrect - hopefully you'll know what I'm suggesting).
Too slow, I think Topper is suggesting similar.
check the cone locking nuts are tight and there is no sideways play in wheel when placed into frame before tightening the skewer
It's common for hangers to sit out a little and flatten on tightening the qr.
Likewise the qr will tighten hub bearings slightly - pros will adjust a tiny bit of play in which disappears on tightening the qr.
What cynic-al said really - if they're cup and cone bearings anyway.
Thanks guys, I'll check the rear mech after work. The hub is a new XT hub. There doesn't seem to be any visible source of rub anywhere.
Might be because it's new then, as long as it doesn't feel tight/nothchy when you spin it by hand?
check the cone locking nuts are tight and there is no sideways play in wheel when placed into frame before tightening the skewer
Actually, kind of the opposite. As noted above, the best way to adjust a cone bearing hub is for it to be just a teeny tiny bit loose (though with the locknuts tight). A properly tight QR applies around a ton (IIRC - or was it a tonne?) of compression, and the bearings tighten just slightly.
So you want to check that the wheel spins super-easily when it's out of the frame, and maybe has just a barely detectable bit of play, but has no play [i]after[/i] fitting it and tightening the skewer.
The axle compresses slightly as you tighten the qr. You need a tiny bit of free play in the bearings with the wheel out of the bike, this will disappear when you tighten the qr. If you're getting drag with qr tight you'll shag the bearings in no time.
Yep, wot the two above said.
I cycled to work on it yesterday, and on the way home the drag on the rear increased.
Pretty sure it's as you guys describe so will loosen the axle tonight.
Do I need a cone spanner for this? I've never serviced a hub before so may need to pick one up in town before heading home this afternoon.
Also, it's an XT centerlock hub if that makes a difference?
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PARKTOOL.COM Had something like this recently on a mates bike - it was actually the smallest cog on the cassette not being on straight!
was all torqued up, etc but when you span the wheel you could see the cog wasn't sitting square - refitted it straight and no issues.
If the cones need adjusting you'll need cone spanners, yes. I've always used two at a time so I can be sure of where the cones are relative to each other, but as long as you can stop the axle moving when you tighten the locknut you'll be ok with one. Check the size; been a while since I did one but IIRC Shimano rears are usually 15mm.
Centerlock shouldn't make a difference as far as I'm aware.