Spidertrax Double Shear Rear Caliper Brackets make it easy to install 14″ (355.6mm) diameter high-performance calipers & rotors on your Spider 9 rear axle. The lower caliper bolts are upgraded to 7/16″ (11.1mm) diameter using a double shear design, and side gussets connecting both caliper brackets adds rigidity for preventing caliper deflection. All in all, this new setup provides the strength needed for running more aggressive brake pads and the durability needed for running longer off-road races. These laser cut brackets are designed to work with all Spidertrax UEC style full floater end cups and Wilwood calipers. Due to caliper tolerances outside of our control, the installer is required to weld these brackets together with calipers on hand; welding not included. Spidertrax Double Shear Rear Caliper Brackets come complete with laser cut brackets and all hardware needed for the final install. CLICK HERE for a copy of the installation instructions.