Rear wheel shifting under load

[Scabutz]

I've dusted off my very old MTB for a winter of commuting. Put a new rear wheel on, new tyres etc. All fine except for a slight problem. If I put a significant effort in, the rear wheel twists in the drop out and the tyre jams against the frame.

First thought was obviously QR tightness. I have tightened and tightened it til its bd tight and it still does it. Its far tighter than on any of my other bikes and it still does it.

Anyone else had this or have any ideas? Could the frame be buggered?

[gazza285]

Sounds like a crap QR, have you tried another?

[troc]

Very old mtb could mean it has an old hub with cup and cones etc - maybe it's loose and/or buggered.

[syko89]

Is there any side to side play in the rear wheel?
Do all spokes have tension?

[anonymous-user]

Long shot, but is the frame cracked?

[Scabutz]

JPJPJP said:

Long shot, but is the frame cracked?

This is what I thought. The rear wheel is brand new as the old one was buggered. When I corner it feels skittish. For the life of me I can't see any crack though.

Brand new chain snapped on way home tonight. Think the whole bike is fked.

Halfords have a Carrera MTB for 250. Might just but that.

[keith2.2]

it wouldn't be unheard of that a weld on the chainstay or seatstay has cracked and you'd never spot it unless you got a mate to help twist the rear triangle around while you looked.

[whatleytom]

Sounds like dodgy freehub bearings to me. If they have play that'll cause ghost shifting, and may end up snapping a chain. Not sure on the skittish handling though.

[Scabutz]

whatleytom said:

Sounds like dodgy freehub bearings to me. If they have play that'll cause ghost shifting, and may end up snapping a chain. Not sure on the skittish handling though.

There is definitely ghost shifting on the inner cogs, but the rear wheel is brand new. The guy in the shop put it in the jig and check it over when I bought it.

Although I cant see why I am sure the frame is moving. It only happens under load which I can't replicate when the bike is in a workstand.

[keith2.2]

Load on which side?

The chances are that the frame is flexing on the opposite side. Check the welds.

[upsidedownmark]

There's another, much simpler possibility - crummy dropouts that don't fit the axle stub terribly well. If that's the case, no amount of skewer tension will stop the wheel skewing under real load; the skewer stops it falling out - the 'nubs' on the hub that sit in the dropouts locate it. The cheap answer is to cut some strips out of an empty beer/coke can and use them as shims.