31. Along with a set of 35-inch Nitto Terra Grapplers, we've got a set of 35-inch Dick Cepek Mud Country tires waiting for the dirt. The Cepek Mud Country has generous voids between the lugs, so it should self-clean well. At the same time, we expect it to be well-behaved and fairly quiet on the road for a mud tire. We'll be running both sets of tires and will report our findings later on.