Indirect TPMS (Tire Pressure Monitoring System) is a type of tire pressure monitoring system that does not use physical sensors inside the tires to measure the air pressure directly. Instead, it uses data from the vehicle’s ABS (Anti-lock Braking System) or wheel speed sensors to infer tire pressure.
Here's how it works:
- Indirect TPMS monitors the rotation speed of each wheel. When a tire loses pressure, its radius decreases, causing it to rotate faster than the other tires.
- The system detects these speed differences and identifies that one or more tires may have low pressure.
- Based on this information, the system alerts the driver about a potential issue with tire pressure.
Advantages of Indirect TPMS:
- Cost-effective: It is cheaper to install compared to direct TPMS, which uses physical sensors in each tire.
- No need for battery changes: Since it relies on the vehicle’s existing sensors, there are no batteries in each tire, reducing maintenance costs.
Disadvantages:
- Less accurate: Indirect TPMS cannot provide exact tire pressure values; it only signals when there's a significant difference in tire pressure, which may not be as precise as a direct system.
- Relies on vehicle dynamics: Indirect TPMS can sometimes give false alerts if the vehicle’s load or road conditions affect wheel speed, potentially leading to incorrect tire pressure warnings.
Overall, indirect TPMS is a more affordable and less complex system compared to direct TPMS, but it comes with trade-offs in accuracy and reliability.
