Press down on the small needle in the center of the valve (the little tube that sticks out of the tire) to let air out, you can do this with a screwdriver, just be careful not to puncture it.
The time it takes to let air out of a tire depends on the size of the tire's valve and the pressure inside the tire. Generally, it can take a few seconds to a minute to fully deflate a tire.
deflate
Click on the left front tire and then click on the knobish thingo and it will let air out.
Deflate is to allow air to escape from a balloon.
On Cryptids Island to let the air out you must first offer to help the gentleman. Click on the truck tire and click down on it til enough air comes out. He will then reward you for your kind being and thoughtfulness.
let some air out of the tire
deflate
The tire will go flat.
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
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.
To deflate a bike tire, you can use a valve tool to press down on the valve stem and release the air. Alternatively, you can simply press the valve stem with your finger to let the air out.
Because when you compress a gas like airit gets warm - which is what happens to the pump. And when a gas like air is allowed to expand, which is what happens when you let it out of the tire, it cools off - which is what happens to the valve.