Hoosier MX Dirt Bike Tire 110/90-19 C100 IMX30 is optimal as a rear tire on a 250 & 450 Off Road bikes in Supercross and Motocross. The new C100 Construction offers more performance and longevity over the previous version. This construction now complements the 07110 MX25S and MX30S to help balance the stiffer construction on the front end. The IMX30 compound is great for hard packed conditions or for the rider that needs a tire with a longer lifespan but still the performance needed to win. Optimal air pressure range is 12-14 psi.