Uneven flat spotted tyre?

[j4ckos mate]

I had a strange one on the wife's car today. (Saab93 cab)
It had A thump thump thump thump on the wheel when being driven.
Took it to the garage and they couldn't find anything, so took it to the tyre bay
He reckoned the tyre was flat in places.
20p shaped.


I was dubious at first until he put it on the wheel roller and spun it Round and your could feel it was uneven
He put a new tyre on and it's fine

What would cause the tyre to wear in such a way??

[andyiley]

Don't know what causes it, but I have had it before with Pirelli & Courier tyres.

[Mr2Mike]

j4ckos mate said:

What would cause the tyre to wear in such a way??

Was it actually uneven tread wear? If a tyre is visibly 20p shaped then it's more likely some kind of failure within the tyre carcass IMO. Knackered dampers can cause a pattern in the tread wear around the circumference though.