Is there any difference, for the same type of tyre, between the tyre manufacturers in the game?

No, not yet. Maybe there will be later, but currently no.

use search button before opening a topic please.this was discussed before many times.and the answer is definitly NO !

Four manufacturers are selectable in the car setup screen. For now, the different manufacturers are selected only for graphical effect

http://www.liveforspeed.net/?page=t_a_u

I did search for "Tyres" but try it

Quote from TyresHot :

use search button before opening a topic please.this was discussed before many times.and the answer is definitly NO !