Rolling resistance refers to various forms of resistance against driving force when a car is in motion. It is mainly caused by hysteresis loss from the flexing of tires as they rotate, accounting for approximately 90% of rolling resistance. Radial tires have lower rolling resistance than bias tires. Maintaining the appropriate tire pressure is important to minimize unnecessary distortion and energy loss. Friction between the tire and road surface accounts for less than 10% of total rolling resistance. Wind drag resistance is minimal at low speeds.