Troy Cox of Cecil and Sons Discount Tires stopped by GDGC to answer our questions about how to make sure the tires on our vehicles are properly inflated.1) Of all the varying car information and recommendations out there to confuse us, one area seems to have fairly universal agreement: the importance of proper tire pressure.
Study after study and survey after survey, the same results keep popping up: a significant number of vehicles on the road have at least one underinflated tire; of those with one underinflated tire, most have all tires underinflated. Running tires low is a good way to wear them out prematurely, but that’s really the least of your worries. The EPA estimates approximately 1 billion gallons of gasoline are wasted each year due to underinflated tires, so you’ll pay more in terms of higher gas consumption as well as wearing your tires out faster. There are also significant handling/control issues with underinflated tires—cornering and braking are adversely affected, hydroplaning resistance is reduced, and tires can even fail due to the heat buildup caused by running them low. The NHTSA estimates that underinflated tires are a contributing factor in approximately 600 deaths and 30,000 injuries each year. So yes, everybody in the automotive industry agrees: keep your tires properly inflated.2) We’ve talked about the importance of checking tire pressure regularly, of having an accurate air gauge and using it, but that’s not so much of an issue with newer cars and their tire pressure monitoring systems, right?
Well, given the average age of the U.S. vehicle fleet is currently 11 years, there are a huge number of cars, trucks, vans and more out there that need their tires checked with an air gauge on a regular basis. We didn’t start seeing significant numbers of vehicles with tire monitor systems until the 2004 model year, and it was the 2007 model year when all U.S. cars and light trucks were required to have tire monitor systems, so not everyone can toss their air gauges out just yet. More to the point, car manufacturers were allowed to use either direct or indirect systems. Direct systems have a sensor in each tire/wheel assembly that directly measures air pressure to warn you if a tire or tires are low. Indirect systems use the anti-lock brake sensors, which count tire rotations at each corner, to indirectly measure pressures and assume a low tire when one tire’s rotational speed differs significantly from the other three. As the tire loses pressure it loses height and subsequently turns more full rotations to cover the same distance as the other three which eventually will trip a warning. The problems with indirect systems are: 1) they can’t tell you which tire is low, 2) they are much less accurate than direct systems and can allow a tire to get dangerously low before warning you, and 3) since they can only react to differences if all your tires are low you get no warning at all, so you’ve still got to check your tire pressures on a regular basis.3) So how do we know if we’ve got a tire pressure monitor system and if so, are there any things we should be doing to make sure it’s working properly?
When you start your vehicle, there are a number of warning lights that come on briefly as the vehicle “self checks” those various systems—if they’re working correctly, the lights then go off in five seconds or so. The tire pressure warning light is a symbol than is supposed to look like the cross section of a tire with an exclamation point in it, and is often described as a U with a flattened bottom and an exclamation point in it. If you’ve got that symbol lighting up on your instrument panel, you’ve got a tire monitor system and if it turns off after briefly lighting then the system should be working properly.
You do want to make sure that, if the vehicle doesn’t reset itself after service, your service facility resets the system if necessary to make sure the car knows which tire is where. This is typically only necessary with a direct monitor system as the indirect system doesn’t typically report on specific tire position or actual tire pressures.
There are a couple of issues you do need to be aware of; first, you really need to keep valve caps on the tire pressure monitor stems as dirt and moisture getting into them can cause damage—either mechanical or corrosion—that could necessitate early replacement. It also needs to be the right kind of cap—on the aluminum stems you should use either an aluminum or plastic valve cap. If you use a steel cap it can corrode due to the dissimilar metals and the weak electric current in that stem (it acts like an antenna) and become permanently lodged on the end of the aluminum stem. If that happens, then the first warning you might get is when you try to remove it to add air or service the tire and the end of the aluminum stem strips or breaks off. Then, you’re buying a replacement tire monitor stem. Eventually, as they’re sealed units that are battery operated, the battery will fail and you’ll be buying new monitor stems anyway. Given they can range from $50-$125 each and each vehicle with a monitoring system has at least four there’s certainly a temptation to just snap a standard stem in the wheel and keep going. But this is a federally mandated motor vehicle safety system, so you’re unlikely to find a service facility that wants the potential federal charges associated with being caught disabling a safety system.Cecil and Sons Discount Tires is family owned and operated since 1973; three generations of our family serving, in many cases, third and fourth generations of our customer’s families. Cecil and Sons has tires, custom wheels, alignment and suspension repair, brakes, preventative maintenance and light line mechanical service.Cecil and Sons Discount Tires
204 East Morrow Road
Sand Springs, OK
4002 South St Hwy 97
Sand Springs, OK