Created as a championship-caliber trials tire, the D803 also delivers in a wide range of conditions, which makes it perfect for trail riding. Compliant carcass construction for excellent traction. Radial-design rear tire works great for off-road trail riding. This is a 4.00-18 rear tire. Traction is amazing and trail damage is minimized with the less aggressive pattern. If you have never tried a trials tire before, give it a whirl, you will be amazed. Not great in muddy conditions.