i sent an email to nitto,and this is the reply i recieved.can't wait for the other sizes!!

Thank you very much sir for taking the time to e-mail us. Nitto Tire North
America, Inc. will be debuting the mud tire called, "Mud Grappler" this
fall. At this time there will be one size available this fall and a wider
selection will follow in the future. The size that will be offered this
fall will be 38x15.50R18 with a "D" load range. For more information on
this tire please look at the June 2003 issue of "4 Wheel Drive & Sport
Utility Magazine." Thank you again for your question and best regards.

Koji Watanabe
NITTO TIRE NORTH AMERICA, INC.