Rear wheel off centre

milanino-branca

I have been servicing a friends bike and when i came to the rear wheel I did a hub service and checked the dish of the wheel before truing it. What i noticed was the dish was miles out so i rectified that and trued the wheel. On replacing the wheel into the drop outs i noticed that it does not want to sit in the middle of the chain stay naturally. Eventually i managed to get it to sit in the middle then noticed it is sitting closer to one side of the seat stay than the other. I removed the wheel and checked it again……the dish was correct and trued. It is an old MTB and i am beginning to think the dish has never been correct and that maybe the frame is out of line too.
ANY advice would be gratefully received.
Thanks
MB

supersonic

Does sound like frame alignment or bent dropouts.

nicklouse

some bikes use a zero dish wheel.

what is this OLD MTB?

milanino-branca

It is a British built Falcon. Have you heard of it?

milanino-branca

The wheel is not a zero dish wheel and also the wheel had to be dished to the drive side.
I am leaning towards frame alignment or bent dropouts.