Wheels, seals and how to pick a good sensor: TPMS tips from the experts

Dec. 1, 2007

As tire dealers bring themselves up to speed about tire pressure monitoring system (TPMS) technology, questions remain about system compatibility with aftermarket wheels, the effects of tire sealants on sensors, and other subjects.

Representatives from TPMS sensor and scan tool manufacturers addressed these concerns during a series of panel discussions moderated by Tire Industry Association Senior Vice President of Education and Technical Services and Modern Tire Dealer contributor Kevin Rohlwing.

“If you’re installing aftermarket wheels, you need to make an effort to get the sensor to work inside the wheel,” said Rohlwing. “If you can’t, you’re not in violation of the law, unless you disable the system. TPMS is not required to operate with aftermarket equipment.”


However, Carl Wacker, global vice president of sales and marketing for sensor manufacturer Schrader Electronics Ltd., offered a caveat aimed at tire dealers who sell tire and wheel packages to car dealerships. “The TPMS has to be compliant at the first point of sale for the OEM. If you install an up-sized set of wheels and take the sensors out -- and it’s before the first OEM sale of the vehicle -- the system isn’t in compliance.” Wacker also discussed how various substances interact with TPMS:

* Nitrogen has no effect on sensor performance, he asserted. “Don’t worry about nitrogen.”

* Balancing beads and powders “are not overly common in the passenger car industry, but powders can contaminate the sensor port. Beads could damage the sensor housing over time.”

* Tire sealants can affect sensor ports, he said. “What does a sealant do? It clogs holes. All sensors need access to gas; if the sealant seals up the hole, the sensor will not (take accurate readings). And aerosol sealants could physically damage a sensor due to propellant chemistry.”

In the event of a clogged sensor, “do not attempt to clean the sensor port with a sharp object,” according to Wacker. “Sensors are designed to be compatible with most of the common materials found in a service bay, but they aren’t bulletproof.”

Jean Christophe Deniau of Siemens VDO advised dealers to attach sensors properly.

“Some aftermarket centers use whatever they can to affix a TPMS sensor on a wheel. Improvised mounting equipment could lead to the detachment of a sensor while driving.”


TPMS scanners

Scott Holloway, general manager for scanner manufacturer Bartec USA LLC, also listed prerequisites of a good TPMS scanner:

1. Functionality. “Because you’re waking the sensor up (with your scan tool) and forcing it to read data, you want to have the right power level. If you have too much (power), you can turn on more than one sensor.”

2. Easily upgradeable. “You don’t want to have to buy extra components. If your hardware can’t deal with various frequencies, it could get costly.”

3. Cycle time. “You don’t want to wait for the sensor to respond after you activate it.”

The ability to transfer data also is important, adds Holloway. “Can you store data and use it? Can you print it in a report?” Having hard copies of data will come in handy if customer questions arise, he says.

“The users of scan tools need to educate consumers on what TPMS is and what its benefits are,” said Chris Batts, TPMS product manager for K-Tool International, a TPMS scan tool supplier.