STI Roctane XD Radial Tire (27x9-14) STI Tire & Wheel continues to set new standards for creative innovation in the ATV / UTV tire industry with the introduction of the all-new Roctane XD. This new extreme duty radial tire is loaded with features to meet the highest demands of today's machines and consumers. A heavier denier nylon cord maximizes tire toughness while retaining flexibility for a comfortable ride. The Roctane's unique, non-directional tread design and wide profile footprint deliver smooth, quiet operation and precise control. STI's exclusive new RocWall sidewall construction features reinforced lower sidewalls and extra-wide tread belts for added shoulder protection and stability.