Off-road tires are a category of vehicle tires that use deep tread to provide more traction on unpaved surfaces such as loose dirt, mud, sand, or gravel. Compared to ice or snow tires, they lack studs but contain deeper and wider grooves meant to help the tread sink into mud or gravel surfaces.
Knobby tire on a 2008 Motovert pit bike.
Different treads on knobby mountain bike tires
Example of a mild all-terrain tire
Image: 2012 Honda Ridgeline RTL on the trail
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, providing a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, designed to match the vehicle's weight and the bearing on the surface that it rolls over by exerting a pressure that will avoid deforming the surface.
Assorted new automotive road tires, showing a variety of tread patterns.
Tractor tires have substantial ribs and voids for traction in soft terrain.
John Boyd Dunlop on a bicycle, c. 1915
Studded winter tire