help with rear tyres cupping (scalloping)

[theexey]

hi
does anyone have any experience of cupping of the rear tyres. i thought the wheel bearings needed replacing cause of a droning noise at about 30-40mph. when i jacked the car up to take a look i could feel pronounced cupping of the inside edge of both rear tyres.
my car is an 05 plate tdi its only got 21k on the clock and still has the original tyres on, oh and it has sports suspension as a factory fit extra (ex demo car).
i was wondering if anyone had experienced this, or knew how to rectify the problem. i'm pretty sure there's been no suspension damage as its both sides and the car was clear on history check
thanks
craig

[John140]

My 07 A4 Avant sort of does this on the back.

My rear tyres are wearing very well, but the outside of both rears are identically 'feathered', ie sharp edges to the edges of the tread blocks when running your hand over the tyre.

I've had the geometry checked by Audi and by a skilled independant and nothing was seen to be out of spec.

IN FACT the official Audi service manual on DVD states that a slight sawtooth wear pattern is normal, and to only work if the edges of the tyre are wearing excessively.

I havent experienced the droning noise from the back.

BUT, when I put the back tyres on the front (complete with feathering) I got the droning from the front until the tyres wore right down.