Direct TPMS methods use pressure sensors to measure pressure in each of the four tires. Then these sensors transmit the pressure data via a wireless RF transmitter to a central receiver. The receiver communicates to a display that informs the driver which tire is underinflated. The tag in each wheel is designed to send a warning signal when a tire's pressure drops below its specified safety level. Tire-mounted pressure sensor is shown in Figure 1. Under-inflation has been cited as a cause of tire failures such as tread separation or tire blowouts. It is also responsible for shortening tire life and reducing fuel economy.

Indirect TPMS:

Indirect systems employ wheel speed sensors on a vehicle's anti-lock brake (ABS) system to track each tire's rotation. The premise is that under-inflated tires have a smaller radius, resulting in a higher rotational speed compared with a fully inflated tire. The sensor is supposed to detect the faster rotation, and the system alerts the driver. In practice, this change in radius is small, making indirect measurement less reliable than direct pressure measurement.

Technical features

•  Constant monitoring of inflation pressure, tire temperature, tire sensor identification and battery life while driving and when standing still

• Prevents the consequences of low tire pressure through early detection:

  • Punctures (approx. 80% of punctures are caused by inadequate tire pressure)
  • Increased tire wear due to added flexing work
  • Increased fuel consumption due to higher rolling resistance

• Always provides optimum driving comfort
• Driver is informed immediately of deviations from setpoint
• In a typical temperature profile functionally reliable up to 120C, temperature-resistant up to 170C
• Reliable up to 2000 g acceleration (static) and approved for numerous high-speed vehicles
• Vibration resistant and even suitable for use with snow chains
• Flexible design for almost all rim applications
• Tire inflation pressure can be individually specified and therefore tailored exactly to the loading of the vehicle
• Self-learning system with automatic individual wheel detection, leading to faster and more efficient wheel changes
• Saves the troublesome, inconvenient and inaccurate testing at gas stations (the tires warm up while driving to the gas station, while the specified values apply to cold tires)
• Reduces fuel consumption and the release of CO2 into the atmosphere

How to keep your tires properly inflated:

 1:   Check tire pressure at least once a month and before going on long trips. Since temperature affects tire pressure, it is best to check tires when they are cold, i.e. haven't been driven on for at least three hours.

2:   Fill your tires with the pressure recommended on the tire label, located on the drivers door frame, sill or edge.

3:    If you have any questions about your tires or maintenance, check your owners manual or consult your dealer.