PeachParts Mercedes-Benz Forum - View Single Post

Luke@tirerack · #4 12-13-2006, 04:32 PM

Mercedes-Benz

An Update on Tire Pressure Monitoring Systems and Aftermarket Wheels

A direct tire pressure monitoring systems (TPMS) will be standard equipment on every vehicle sold in the U.S. after September, 2007. The criteria for TPMS standardization is that the vehicle must have only four wheels (no dual-wheeled trucks or motorcycles), and weigh less than 10,000 lbs.

Mercedes-Benz has used direct and indirect TPMS technology (see TPMS Facts below) since 2001. BERU and Siemens valve sensors, carried by The Tire Rack, are used in their direct TPMS. 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, the sensor will not fit properly. Wheel manufacturers are aware of the issue and are rushing to get most of their wheels TPMS-compatible.

The Tire Rack's fitment specialists have carefully determined which wheels that are currently available will be compatible with the system installed on your vehicle.

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If you have any questions about the wheel you're considering, call or post your question for confirmation that it will be compatible with your TPMS.

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TPMS Facts

Direct TPMS use a sensor in the wheel/tire to wirelessly relay pressure back to the driver via a display inside the vehicle. Some vehicles have a digital screen that continuously shows all four tire pressures (five if spare has sensor). Others simply flash a "low tire pressure" light on the dash. Additionally, there are two different styles of sensors for a direct system: a valve sensor and a strap/band sensor. Only valve sensors are used on Mercedes-Benz direct system-equipped vehicles. If you bought an aftermarket SmarTire TPMS, its sensors are held on by a strap around the barrel of the wheel.

Indirect systems work in conjunction with the ABS wheel speed sensors that “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). The ABS system will recognize this change and alert the driver with a flashing light and possibly a loud chime. The Mercedes-Benz indirect systems do not affect the fitment of aftermarket wheels.