ive gotta set of 36x14.50x15 parnelli jones dirt grips on my 1 ton swapped k5...they do suprising well @ street pressures, i.e 32psi...its when aired to to 10psi n below (havent been any farther than that personally) that they become a different animal...makes for about a 16" wide track...extremely aggressive after that...wear good also...not sure of other sizes tho...