Air leaves a tire when the tire valve is open due to the pressure. The pressure outside of the tire is lower than the pressure inside the tire.
Air leaves a tire when the valve is opened due to the pressure difference. Since the tire has more pressure than the air outside, the tire air will escape until the pressure equalizes.
Because the air inside the tire is under pressure. Gas always flows from a region of higher pressure to a region of lower pressure. As the pressure inside the tire is greater than the pressure outside, the air always comes out of the bicycle tyre.
Because, by pressure differential, there is a gas flow from the high pressure tire to the lower pressure environment.
if you are asking about the air valve on the tire to add/let out air then it is a schrader valve or an American valve
It is the air valve on the tire, where you put air into the tire.
The basic function of an air valve is to control the release of air that is under pressure. Common places where an air valve would be used is on an inflatable tire. It is used to add more tire pressure to the tire.
To inflate a tire with a Schrader valve, follow these steps: Remove the valve cap from the Schrader valve on the tire. Attach the nozzle of the air pump to the valve. Pump air into the tire until it reaches the recommended pressure level. Remove the nozzle and replace the valve cap.
The Schrader valve may not be allowing air to enter the tire due to a blockage or damage to the valve stem, preventing the valve from opening properly to let air in.
It's likely there's a rupture in the diaphragm that pulls the air into the chamber and then pushes it out to the valve. There are two "reed" valves in the pump that only allows the air to go in one direction with each valve. So when you pull up on the handle to fil the pump, one valve allows air in, but not out when you push down on the handle. Another valve at the bottom of the pump allows the air out when the handle is pushed down, going to the tire. There is another vavle on the tire that is opened only with the pumps adaptor, to allow air into the tire.
I have heard the shradder valve is the tire valve stem ( internal valve ) that keeps air in the tire or else you will have a flat.This valve has many applications including air tanks
Your bike tire valve may be leaking air due to a damaged or worn-out valve core, a loose valve stem, or a puncture in the valve. It is important to inspect and replace the valve if necessary to prevent further air leakage.
To put air in a bike tire, first remove the cap from the valve on the tire. Then, attach the pump nozzle to the valve and pump air into the tire until it reaches the recommended pressure level. Finally, remove the pump nozzle and replace the valve cap.