Where should tire pressure be tested?

Testing tire pressure should be done at the valve stem because this is the point where air is added or removed from the tire. The valve stem is specifically designed to hold the air inside the tire and provide access for inflation or deflation. When using a pressure gauge, placing it directly on the valve stem allows for an accurate reading of the tire's internal pressure.

The valve stem is also designed to seal properly in order to prevent air loss, which is essential for maintaining the optimal tire pressure. Taking readings from other areas, such as the tread level, underneath the vehicle, or near the axle, would not yield accurate measurements of the tire's pressure for several reasons. They do not provide direct access to the air inside the tire and can lead to misinterpretations of the tire's condition. Therefore, testing tire pressure at the valve stem ensures both accuracy and relevance to tire performance and safety.