A wheelchair tire is a tire that fits on the wheel of a unicycle, tricycle, quadracycle, bicycle trailer, or trailer bike. They may also be used on bicycle and hand cycles, especially for racing. wheelchair tires provide an important source of suspension, generate the lateral forces necessary for balancing and turning, and generate the longitudinal forces necessary for propulsion and braking. They are the second largest source, after air drag, of power consumption on a level road.