Where on a tire should a technician test its pressure?

Testing tire pressure should be done at the valve stem because this is where the air is added or released from the tire. The valve stem houses the valve that seals the tire and enables you to inflate or deflate it. Using a pressure gauge at the valve stem allows for a direct measurement of the tire's internal pressure, which is essential for safe operation and optimal vehicle handling.

Measuring the pressure at other locations, such as the sidewall, center cap, or tread, would not yield accurate readings. The sidewall is where the tire's specifications and maximum pressure ratings are printed, but it does not reflect the actual air pressure inside the tire. The center cap is merely a decorative component and has no relation to tire pressure. The tread is the part of the tire in contact with the road, but again, it does not provide any means to assess the air pressure within the tire. Therefore, the valve stem is the only appropriate location for accurately testing tire pressure.