If it was me that Racer was referring to, our roads here in NZ are a very coarse chip.
I read mileages of 7-8-+K miles out of tyres, I'm lucky if I get 4-5K Miles from mine.
Also, I'll note that the center of the tyre is loosing the tread, as it does, so I head for the hills and "match up" the sides of the tyre with some hard, exhilarating acceleration out of corners.
The way I see it is the tyre is just about gone anyway, so burning up the tread on the sides is fun for free