What are some types of TPMS are in use today?
Indirect System: Uses the ABS wheel speed sensors to monitor the rolling radius of the wheel and tire assemblies. Rather than directly monitoring tire pressure, the ABS measures the rotational speed of each tire. If one tire starts to spin faster than the others, the ABS determines that a tire has become smaller and has likely lost air pressure. This is done by measuring tire rotations within a given distance. A tire that has a reduced rotation that meets a predetermined percentage is considered to be low on air pressure. Direct Systems : This system monitors the air pressure in the tires with a wheel mounted sensor. The direct type of TPMS can detect actual pressure levels and transmit the information to the driver more quickly. Tires are monitored individually by sensors attached to a special tire valve, or strapped to the drop center of each wheel. Each sensor monitors and transmits tire pressure and temperature every few minutes. The temperature is monitored to compensate for cold
