US publisher says TPMS systems still need manual pressure checks

ERJ staff report (DS)

Costa Mesa, California -- NADAguides.com, a US publisher of used car information and pricing guides, said Tire Pressure Monitoring Systems (TPMS) don't provide enough information to let drivers achieve optimum handling or fuel efficiency, making checking tyre pressure the good old fashioned way still important for car safety.

There are an estimated 21 million drivers in the US today who own a vehicle with a TPMS, according to a recent study by NADA. According to the study, roughly 85 percent of 2008 model year vehicles use the indirect pressure monitoring system, while approximately 15 percent use the more sophisticated direct measuring system.

According to the NADA report, direct systems arguably give the driver more information at his fingertips. However, the Federal Standard for all TPMS requires a safety warning only when tyre pressure has dropped 25 percent below the manufacturer's recommended cold tyre pressure. This means the driver of a car with a commonly recommended tyre pressure of 35 pounds per square inch (PSI) would be warned when tyre pressure drops to about 26 PSI. Research shows, however, that even a slight drop in PSI can compromise a vehicle's handling and safety, especially when it's loaded with passengers or cargo.

What's more, less-than-optimal tire pressure means less-than-optimal fuel economy. A drop of six PSI, for example, translates into a 10 percent decline in fuel economy, even though it often wouldn't trigger a TPMS warning.

According to Baukus Mello, systems improved in 2006 when they became more sophisticated as a result of a federal standard that began to be phased in to bolster car safety. About 70 percent of 2007 model year vehicles came equipped with TPMS, with all passenger vehicles being required to have these systems for 2008 and beyond.

"A driver's best tyre safety resource is manual monitoring, the good old fashioned way," said Mello. "A monthly visual inspection of your tires coupled with the use of a tyre gauge -- preferably digital versions as these are the most accurate to check pressure -- remain the best ways to make certain your car, truck or SUV is operating safely and economically."

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Press release from NADA