WHAT IS CUSHCORE? CushCore is an engineered foam insert that mounts inside a mountain bike tire. It divides the inner volume of the tire in half, with air underneath the tread and the CushCore insert next to the rim. Cushcore absorbs impacts, reduces vibration, and adds lateral stability to the tire. These characteristics translate to a more controlled, comfortable, and faster ride. This system is designed to be used with tubeless-ready or tubeless converted mountain bike rims and tires. CushCore is compatible with tubeless tire sealants. A specially designed tubeless air valve is included with each insert. The air valve allows air to move through the valve without becoming obstructed by the insert.