Here’s a simple addition to our Spider 9 brake product line that will mean a lot to a number of Ultra4 racers. For over a decade, we’ve been successfully running 14″ diameter rotors. Solid rotors at first, followed by vented rotors as of recent. These larger diameter rotors work amazing for rock racing, providing excellent braking power at high speeds (racing) along with ultimate stopping power at low speeds (crawling). With small exception — caliper to wheel clearance is tight, and on some newer Ultra4 builds (IFS specifically comes to mind) it becomes a bit too tight. Enter the GT-36 Series 13.5″ Vented Rotor.

This rotor starts life out as a 14 in. Wilwood GT-36 Vented Rotor, and then finds its way into our machine shop. We take down the outside diameter to 13.5″, chamfer both sides for a clean factory finish, hold less than .005″ position tolerance between the finished OD and brake hat mounting holes, all while maintaining full caliper pad contact. In the end, it’s a simple solution for those that need just a bit more caliper to wheel clearance. Rotors and caliper brackets are in-stock and ready to ship — http://www.spidertrax.com/GT-13.5-in.-Vented-Rotor .