Which scale should I look at on a tire pressure gauge?
1 Answers
Tire pressure gauges generally use the inner scale. Analog tire pressure gauges determine tire pressure by reading the indicated value on the pointer, typically divided into inner and outer scales. The outer scale uses imperial units (psi), while the inner scale uses kg/cm², with the conversion being 14.5 psi = 1.02 kg/cm² = 1 bar. The inner scale is usually preferred because its minimum graduation is 0.1, compared to 1 on the outer scale, making it more accurate. Tire pressure gauges can be categorized into three types: 1. Digital tire pressure gauges: These display the pressure directly, allowing for easy reading. 2. Alert-type tire pressure gauges: These only activate when the pressure is too high or too low. If the dashboard indicates high pressure (typically above 345 kPa), a high-pressure alert will sound, requiring deflation until the pressure drops below approximately 335 kPa to deactivate the alert. For low pressure (typically below 175 kPa), a low-pressure alert will sound, and the pressure must be restored to above 230 kPa to deactivate it. If a rapid pressure loss alert appears, indicating a pressure drop of more than 30 kPa within one minute, troubleshooting is necessary, and the alert will only deactivate after the vehicle's power is completely shut off.
