Gravix^™ race tires are a revolutionary new hybrid design with densely packed biting edges and sipes. They deliver outstanding grip on hard-packed surfaces along with fast and quiet-running precision on pavement. Gravix tires come mounted and pre-glued on tough 2.8″ black RXT wheels for no-hassle, out-of-the-box bolt-on traction. TSM^®-rated for high-speed applications. (fits 12 mm hex, 4WD front or rear, 2WD electric front only)