Thanks for your C&C!
KRiS83: It's not a bump map, I actually modelled the whole tread! I used a tutorial to make it.. you can find it here:
http://www.lwg3d.org/forums/showthread.php?t=16490
Hawktoey:
The tire still needs some tweaking! By bulky do you mean the tread or the whole design of it?