Tire valve definition
A small valve, mounted on the wheel rim of a tubeless tire , that allows air to be added to the tire with an air hose and allows air to be withdrawn from an over-inflated tire by pressing on the little stem at the end of the valve. Some tire valves have little caps to protect against leaks and keep dirt from fouling the valve. On tires with inner tubes , the tire valve is mounted on the inner tube. There are two kinds of valves used: Presta and Schrader .