CushCore Gravel/CX Tire Inserts - Fits 700c x 33-46mm, PairCushCore is an engineered foam insert to be mounted inside a tire, designed to absorb impacts, reduce vibration and increase lateral stability. These characteristics translate to a more controlled, comfortable, and faster ride. Fits tire widths 33mm to 46mm and inner rim widths 19mm to 26mm Inserts reduce rolling resistance which allows for better forward momentum through rough terrain Freedom to run lightweight tires with supple, fast rolling casings