Uneven sprocket wear

[PaulSmith]

While cleaning the bike over the weekend (I do it every 6 months, even when it doesn't need it), I noticed that the teeth on the inside of the rear socket were bright and shiney while the outside of the teeth were their normal greyish brown. Out of interest, I pulled the front sprocket cover and noticed the same thing. The hooks showing normal wear for their age but the outside of the teeth are bright and shiney with clear wear marks and no sign on wear on the inside.

I don't think this is simply the rear wheel being incorrectly aligned after adjusting the chain, but I can't think what else could cause it.

[sirgalahad3]

Bike ever been in an accident or been down the road and hit a curb?

[Simon.Pieman]

Bike ever been in an accident or been down the road and hit a curb?

Puzzled. How would that affect the sprockets and chain?

[sirgalahad3]

A decent bang can twist things out of alignment. Wheel, swinging arm etc. Unlikely but not unknown.

[PaulSmith]

I had thought of that but surprisingly enough, I haven't even dropped it at stand still, let alone crashed it. 

[Dave48]

Would wear in the swing arm or rear suspension bushes/bearings cause this?

[PaulSmith]

Its possible. Can you suggest somewhere to look for evidence? I would have expected wear to result in looseness and/or movement rather then displacement.

[Simon.Pieman]

Its possible. Can you suggest somewhere to look for evidence? I would have expected wear to result in looseness and/or movement rather then displacement.

 Have a look at the rear sprocket profile Paul. Some are manufactured flat on one side -the face that's bolted to the wheel and have the face of the teeth cantered in on the other side -a bit like an old dished dustbin lid. If yours is like this then inevitably the flat side will show wear -but the other side will not because the sides of the teeth are not quite touching the chain sideplates.

[Dave48]

Its possible. Can you suggest somewhere to look for evidence? I would have expected wear to result in looseness and/or movement rather then displacement.

Usual method is to remove rear wheel & then check for sideways play in swing arm bushes. Might need to dismantle rear suspension pivot assembly-good idea to do this now & again to check for wear and condition of seals & regrease roller bearings. They live in a harsh environment with all the wet & s**t thrown up in this area.