CushCore Plus Tire Insert - 27.5"+, SingleCushCore 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. CushCore Plus is well suited for trail, enduro, and downhill disciplines CushCore allows suspension to work more efficiently by requiring less travel to absorb bumps Tire inserts help to protect the rims and prevent flat tires