Traxxas Spiral-Cut Machined-Steel Front Differential GearsSpiral cut 37 tooth ring and 13 tooth pinion front differential gear sets are CNC machined from a solid block of steel. The teeth are cut with a slight curve to minimize backlash between gears and maximize tooth traction with more surface area than straight cut gears. Spiral cut gears are ideal for high torque, high speed, brushless applications.