forgive me if i dont fully understand your question... like real tires all are different.. made differently for the occasion.. in GT5P its all about grip... when GT5 comes out tires are gonna play a vital role, more than just grip.. if that makes any sense.. lol.. anyhow.. in GT5P tire grip ranges from N1 being the lowest to R3 being the highest.. the more grip the better your acceleration, stoping, and cornering.. which to me is far more important than overall top speed.. especially on a track with alot of turns like Suzuka.. i hope i helped out somehow.. if not i apologize.. i tried...