Axial UTB18 Overdrive 48P Portal Gears. Intended for the front portal boxes these overdrive gears improve your UTB18 Capra’s steering radius and climbing ability. With the front overdriven, the front tires will spin slightly faster than the rear and help pull the front faster in turns, resulting in a tighter turning radius. The supplied 25T/16T metal gears are 48 pitch. Package includes two 25T gears and two 16T gears.