Michelin Wild Racer Ultimate Advanced Tire - 29in Gum-X, 29x2.25 The new Wild Race'R is the latest addition to the Michelin Wild range Designed for use on hardpack terrain Provides better handling, greater efficiency thanks to a new tread design, and new architecture on the crown Dual Compound Technology combines a hard layer underneath the surface for protection with a surface layer that is softer to maximize grip Gum-X compound for balanced efficiency and grip