Z speed rated tyres and W/Y rated tyres

[Stedman]

I'm slightly confused, why make a tyre that is rated up to 168/186mph (W/Y), but then another that can go 'past' 150mph?

Now I know you're not going to be fitting linglong Z rated tyres to your Veyron, but what the hell does 150mph+ actually mean?

[JR]

Z is for the best tyre that can be made. When introduced, supercar speeds were a lot lower than they are today so for commercial reasons there are now two sub-groups to the Z classification: W and Y, which suffice for most of us.