The Gorilla Silverbacks are available in the largest sizes! Silverback tread depths are: 27" - 1.5" 28" - 1.75" 30" - 2" 32" - 2.5" Intermittent Lug Bars wrap all the way to the bead. Self cleaning, mud shedding tread design. Soft tread compound. 6 Ply Rating Spacing between tread bars is between 4-1/2" to 6" Rim-Guard feature (No returns on Silverbacks except for a manufacturing defect. In the event of a manufacturing defect the tire would be replaced after inspection.) (The Siverback does not qualify for ProStaff discounts)