BMW TPMS info (FYI)

[doc@tirerack]

Tire pressure monitoring systems (TPMS) are now impossible to run from when buying a new vehicle. Every new vehicle made for sale in the USA has a direct TPM system as standard equipment. There are several exceptions though: the vehicle must have only four wheels (so no dual-wheeled trucks or motorcycles), and the GVWR must be less than 10,000lbs.

We carry all sensors and valves for every model of BMW and Mini up to the 2008 model year. The older model BMW’s and Mini’s that have an indirect system do not need TPMS valve sensors.

The basics of the direct TPMS is that it uses a sensor in the wheel/tire to wirelessly relay pressure back to the driver on some sort of display. Some vehicles have a digital info screen that will show all four tire pressures (five pressures if spare has sensor) all the time. While others might just flash a low-tire-pressure light on the dash. There are also two different styles of sensors for this system: a valve sensor and a strap/band sensor. Only valve sensors are used by the direct system-equipped BMWs, although if you bought an aftermarket SmarTire TPM system, those use the sensors held on by a strap around the barrel of the wheel.

BMW’s indirect system will not affect the choice of switching aftermarket wheels or tires. The system runs off of the ABS/wheel-speed sensors which “count” the number of revolutions of each tire. If the right-front tire is low (25psi) it will spin faster than the left-front tire (35psi), so the ABS system will recognize this change and alert the driver with a flashing light near the gauge cluster and possibly a loud chime.

All BMW valve sensors are currently being produced by BERU and are sold by us in two parts: the sensor component and the metal valve. The size of the sensor shouldn’t be a problem for many wheels, but if the valve hole is in the middle of the wheel’s barrel, then obviously the sensor will not fit properly. The wheel industries are aware of the valve sensors and are rushing to get most of their wheels TPMS-compatible. If you have any questions about the TPMS-fitment on a wheel that The Tire Rack sells, I can look up the wheel and confirm if it will work with your vehicle.

[serbiasrt8]

so,if for example i switch to 22" from 20" inch wheels,and i drive the car,without re setting the system,i might experience the ABS behaving out of the ordinary and also some interference by the DSC?