OVERVIEW: Make your drivetrain stronger on your 1/10 TRX-4 Rock Crawler by installing our Billet Machined HD Spur Gears. Our spur gears are a bolt-on upgrade that replaces your stock molded spur gear (Traxxas OEM part #8053) with heavy-duty steel. The Billet Machined HD Spur Gears come with new slipper pads and are available in the OEM 45-tooth size (#C28199) as well as a smaller 39-tooth size (#C28198) for more top speed. Item Number C28199 Barcode: 91789030631 Item number C28199 is a compatible upgrade part for Traxxas 82056-4 8053