Jaco set of tires and wheels are for 1/10 scale nitro touring cars. Specially made for the high speed demands of nitro touring cars. Mounted on rigid 30mm wide white 6-hole rims. Glued with CA to bond the rubber to the rim. Used by some of the top racers around the world. The hardness of materials is most commonly measured by the Shore Durometer test. This method measures the resistance of foam toward indentation and provides a hardness value. A Shore Durometer is the international standard for measuring the hardness of materials. The symbol for shore coincides with that of degrees. In reference to foam tires, the lower the shore rating, the softer the tire is thus yielding more traction. The higher the shore rating, the firmer the tire is thus yielding less rolling resistance and more speed.