Cooper Discoverer STT Pro All-Terrain Radial Tire - 37X13.5R17 121Q ARMOR-TEK3 CARCASS PROTECTION - Cooper's proprietary and proven full 3-ply carcass construction in the tread and sidewall provides 50% more protection against impact damage than standard 2-ply tires: The third ply is oriented at an optimal angle to the first two ply's to maximize carcass protection in extreme off-road conditions 3-2 INNER TREAD RIBS - The inner tread ribs of the Discoverer STT PRO are positioned in an alternating 3-2 pattern: This unique hybrid design provides a number of significant performance benefits like: reduced road noise, increased stability and handling, superior soft surface (trail) and mud traction, balanced wear, and reduced tendency for vehicle drift commonly experienced on fitments with aggressive off-road tires LARGE DEPTH SIDE BITERS - The Discoverer STT PRO features large, specially-designed cleats of rubber (side biters) on the shoulder area of the sidewall, to enhance traction and grip in muddy or soft terrains and in rock crawling situations where maximum grip is essential: The orientation and design of these cleats promotes traction on inclines, reducing the chances of tire side-slip FLEX GROOVE - The "flex groove" is a small, circumferential groove in the buttress region that generates a designed flex point in the tire: This ability to flex in a predetermined location provides a smoother ride by helping to dampen the impact generated by inconsistencies in pavement, potholes and gravel: In tough off-road situations where tires are sometimes aired down, this groove allows the tread and side biter to better conform and work together when traversing irregular, tough obstacles ALTERNATING MUD SCOOP & ASYMMETRICAL SCALLOP - The asymmetrical scallops on alternating lugs direct mud into the mud scoops to allow the Discoverer STT PRO to pull through muddy terrains with ease: These scoops act as shovels to consistently dig in as the tire rotates: Scoop by scoop the Discoverer STT PRO digs in and will confidently pull your vehicle through the toughest situations