i am servicing the (shimano 105) brakes on my 2007 Specialized Roubaix, and the rear wheel won't stay centered when i clamp the skewer.

it seems fine with no skewer, or with the skewer loose, but when i clamp the skewer, the wheel cocks to one side by several mm - maybe 3 to 5mm.

my brake issue was that the pad on one side was rubbing intermittently - i ignored it for a while, and then couldn't anymore, as there was basically no pad left on that side. i have already taken the pads off, so i'm not sure that the side to which the wheel cocked was the side that was wearing, and when i took the brakes of the bike, i noticed that the whole assembly was loose on the bike, so the brake wear issue may or may not be related to the centering issue.

anyway, the question is...: what do i do about the centering problem?

should i just try a new skewer?

the skewer i am using came with my Neuvation wheels, and i can't seem to find the one that came with the bike, so to try it i have to get a new one.

thanks.

a little more info:

reversing the skewer makes no difference..., but putting the wheel in backwards makes it cock to the other side when the skewer is tightened.

I doubt that changing skewers will make any difference.

Here are a few possible causes of a wheel moving as you close the skewer.

One is non-parallel dropouts which cam the hub as you tighten the wheel. Usually these don't move unless the bike's been in an accident, or for example the hanger was bent when the RD went into spokes. It's also possible that the dropouts are scored by the axle which finds it's favorite spot whenever you tighten.

Another possibility is a bent or broken axle in the wheel. These are often missed on QR wheels because the skewer holds things together. Remove the skewer, and see if the 2 axle ends can move with respect to each other.

While you're at it, check the wheel dish by turning the bike over and dropping the wheel in without closing the QR and note the rim's position, remove and flip the wheel and try again with the cassette on the left. If the hub is in the exact same place but the rim shifts to the opposite side in the stays, the wheel isn't properly dished and needs to be checked and redished. (this test isn't bullet proof and depends on how precisely you can locate the hub in the frame, but it's a good rough indicator bad dish.

Those are the two most likely culprits, so check carefully.

Reversing the wheel was good sleuthing. If it cocked to the same side by reversing the wheel, I would suspect a bent (non-parallel) dropout. But since reversing the wheel reverses the problem, the wheel is the prime suspect, and as said above, it's probably a bent axle.

Our posts crossed in time, You're describing a possible wheel dishing problem. see the last paragraph of my prior post.

thanks.
ummm..., well...., that's exactly what happened about a year ago.

i replaced the RD, and the hanger.

is there a fix for this?

ok..., so the observation that the direction of cocking reverses when i reverse the wheels indicates that the dropouts are probably parallel.

i checked the axle.

when i just held both ends of the axle, i could wobble one end (the end on the cassette side) with respect to the wheel, but i found that the wobbling went away when i hand-tightened a something that seems to be a kind-of nut that sits in a recess of the cassette.

i put the wheel back on the bike, and now, while still not centered, the centering doesn't change much when i tighten the skewer - so i guess that problem is solved.

the off-center direction reverses when i reverse the wheel, so if i understand correctly, that means the wheel needs to be dished..., right?

curiously, the amount that it is off center doesn't seem to be exactly the same when i reverse the wheel - at least to the naked eye.

A few things.

Next chance you get have the drop outs checked for parallelness (is that a word?) by a local shop. It's a job that require special tools, probably not worth owning.

When you flip a wheel and put it back in the exact same place, the centerline will be unchanged. An incorrectly dished rim moves from one side of the centerline to the other, so if it's switching sides, but not symmetrically, not only does the wheel need to be dished, but the centerline is off a bit too. As I said, it's only a rough indicator because the wheel often doesn't get to the exact same position.

One test for a bent axle. With the bike upside down mount the wheel and let it settle by gravity. Leave the QR off and turn the axle in the frame. If the rim moves the axle is bent, which may be the single cause of all your problems.