Magazine for the auto service professional
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42 | February 2016 The survey also found that, while nearly all drivers (96%) agree that driving a car with under-infated tires is a safety issue, nearly half (44%) admit they rarely check their tire pressure. The National Highway Traffc Safety Administration (NHTSA) estimates tire failure causes approximately 11,000 crashes a year. Under-infated tires or worn-down treads are a major cause of failure. NHTSA's Crash Causation Survey found there was an issue with a tire before the crash occurred in nearly 10% of crashes (one in 11). While driving, tires get hot from fric- tion created as the tire constantly fexes. You can replicate the effect by repeatedly stretching a stout rubber band; it warms up quickly. Do this long enough and the rubber band may eventually break. Tire heat damage may lead to tread separation. In the late 1990s, Ford Explorers had high failure rates of certain 15-inch Firestone tires leading to loss of control and vehicle rollovers which caused injuries and deaths. The U.S. Department of Transportation investigated the issue. That investiga- tion resulted in the Transportation Recall Enhancement, Accountability, and Docu- mentation (TREAD) Act, passed by Congress in 2000. Part of the TREAD Act requirements was a way to monitor drops in tire pres- sure. That gave birth to the tire pressure monitoring system. When the TPMS warning symbol appears, it means one or more tires are at least 25% lower than specifed. In a tire that requires 35 psi, that represents about 9 psi low. Beginning on Sept. 1, 2007, all light vehicles (excluding motorcycles and trucks with dual wheels) have been required to have tire pressure monitoring systems. NHTSA estimates that when all passenger vehicles are equipped with TPMS, it will reduce the number of annual motor vehicle crash fatalities by about 120 and the number of injuries by about 8,500. Many motorists don't recognize the icon. It does not look like anything familiar. The temperature icon is a thermometer. The low fuel icon is a gas pump. The low tire pressure icon is a cross-section of a tire with an exclamation point in the center. Most consumers have never seen a cross- section of a tire. Recently, on some vehicles, the driver information center (DIC) spells out a low pressure warning and many systems even report which tire is the culprit. And some have tire fll alerts (horn chirp and/or lights fash when tires are flled to the proper pressure). Numerous states are also getting involved. For example, in 2010, the California Air Resources Board (CARB) implemented a mandatory pressure check on vehicles whenever any emissions service is done, and several states now include a properly functioning TPMS system as part of their periodic motor vehicle safety inspections. Can you proft from TPMS service? There has been some information from NHTSA about properly infated tires increas- ing fuel economy and that TPMS sensors contribute to it. However, there is little proof to back up the claim that the system saves motorists money. Trying to sell customers on the money-saving prospect probably won't land the job. Writing in our sister publication, Modern Tire Dealer, Kevin Rohlwing, the Tire Indus- try Association's (TIA) senior vice president of training, stated that safety is the key to selling the job. The Chassis Here is an example of the newer, snap-in replacement TPMS sensor from Schrader. Photo courtesy of Schrader International