What is Indirect Tire Pressure Monitoring?
2 Answers
Indirect tire pressure monitoring uses the wheel speed sensors of the car's ABS system to compare the rotational speed differences between tires, thereby achieving the effect of monitoring tire pressure. The differences between indirect and direct tire pressure monitoring are as follows: 1. Direct Tire Pressure Monitoring: Direct tire pressure monitoring devices use pressure sensors installed in each tire to directly measure the tire pressure. The pressure information is transmitted from inside the tire to a central receiver module via a wireless transmitter, and then the tire pressure data for each tire is displayed. When the tire pressure is too low or there is a leak, the system will automatically issue an alarm. 2. Indirect Tire Pressure Monitoring: The working principle of indirect tire pressure monitoring is: when the pressure of a tire decreases, the weight of the vehicle will cause the rolling radius of that wheel to become smaller, resulting in a faster rotational speed compared to the other wheels. By comparing the rotational speed differences between tires, the effect of monitoring tire pressure is achieved. Indirect tire pressure alarm systems essentially rely on calculating the rolling radius of the tires to monitor pressure.
From my years of driving experience, indirect tire pressure monitoring is when the vehicle indirectly monitors tire pressure conditions through sensors in the ABS system. It doesn't directly measure the air pressure of each tire with sensors but relies on detecting changes in wheel rotation speed to infer. For example, when a tire has low pressure, its diameter decreases, causing the wheel to rotate slightly slower than the others. The system can detect this difference and then illuminate a warning light on the dashboard to alert you. The advantage of this method is cost savings, as it doesn't require additional complex equipment and can work with the existing ABS. However, the downside is lower accuracy—sometimes it may give false alarms, like lighting up due to uneven road surfaces, or miss small leaks. Safety first, so if the light comes on while I'm driving, I stop immediately to check, avoiding the risk of a blowout. I also recommend manually checking tire pressure monthly to complement the system and prevent surprises during long trips.
