Speedmaster Gilmer drive kits are aluminum machined and precision made for your street/race engines. They provide higher power and torque transmission, improved meshing to reduce tooth jump, greater resistance to tooth shear, and reduced friction to extend their life. The belts use a fiberglass cord wound across the entire width of the belts to minimize stretching. Speedmaster Gilmer drive belts are manufactured from a synthetic neoprene compound that resists heat, oils, ozone, and aging. Tough nylon fabric is then bonded to the tooth surface for greater wear resistance.