planetary gears instead of spider gears will prevent the tires from ballooning but i dont know if you can get a planetary gear diff. for the x1-crt. i can tell you the reason they do balloon however: the diffs. act as limited slip meaning that when you lose traction in the front most of the power goes to the slipping wheels; all this does is lessen the power to the rear and strenghthen the power to the front. aside from planetary gears the only other way i can think of is a pawl 2 speed instead of a center diff. much like the ones used in the mammoth st RTR