Hard to believe that something so simple can have a profound impact in so many areas, but a regular check of your car’s tire pressures benefits you financially while improving the world around you. But how?
A few basics (we’re not going to launch into Tire Design 101 here, so you can safely keep reading). A car needs tires to do four basic tasks: carry the weight of the car, turn the car, stop the car, and accelerate the car. You could pretty much achieve the same with solid rubber tires that need no air, but then it’d be like riding in a Wells Fargo stagecoach. No, air is definitely what you want filling your tires.
When your car was designed, the auto manufacturer met very early in the process with the tire manufacturer, providing specifications for exactly the type of tire the car maker wanted to install on this new model.
While the automaker’s engineers were working out details like whether the cup holders should be able to accommodate a Big Gulp, the tire engineer were off trying to achieve all the handling, performance, wear, fuel economy and noise requirements of the car maker while meeting the price per tire the car maker was demanding (which is usually not much). In other words, the tires that came with your new car have a great deal of hardcore engineering in them, and weren’t just whatever the tire factory had the most of in its warehouse.
One of the criteria agreed upon by the car maker and the tire company is the recommended tire inflation pressure. This is the pressure that, after extensive testing both on vehicle and on enormous laboratory test rigs, the two companies decided would provide the best combination of fuel economy, wear, handling, braking, and acceleration. You’ll find the proper inflation pressure clearly marked on a tag inside the door of your car, in your owners’ manual, and approximately 1,247,742 places on the internet (give or take). The number marked on your car (for example 32 PSI) is the number you use to inflate and check the tires (plus a few rules we’ll throw at you in a minute).
One fallacy that continues, not just among consumers but at some tire shops as well, is that the proper inflation pressure is what’s stamped on the tire. In the case of MOST cars in the US and Canada, that’s 35 psi (pounds per square inch). That’s actually the MAXIMUM inflation pressure. The basis of this fallacy is the classic “if some is good, more is better” argument: If the car maker lists 32 psi, I’ll get better fuel economy at 35 psi because of the lower rolling resistance of the “harder” (more highly inflated) tire. Well, maybe. But you’ll increase tire wear, especially in the middle of the tread and reduce the car’s other capabilities including, most importantly, wet braking. And even if the extra tire pressure only increased stopping distances by 6 inches from 30 mph, haven’t we all, at least once, wished we could have stopped 6 inches sooner?
So now we know why we don’t want to OVER inflate our tires, and perhaps you’re now think UNDER inflating might be better. Sorry, game over, thank you for playing. Underinflation can lead to even more problems than overinflation. First, you’ll wear the tires much faster, especially on the outside edges. As the tire tread is not flat against the road, the car uses the edges of the tires when turning which speeds-up shoulder wear. The most dangerous outcome of underinflated tires is that the tire can overheat and basically blow out the sidewall. This is due to excessive flexing in the sidewall area which heats up and causes the tire to fail. Almost all of those strips of tire tread you see along the side of the interstates came from underinflated tires. By the way, did you know that most tire wear comes from turning and stopping? If all you did was drive coast-to-coast back and forth on the interstates your tires would last a very, very (very) long time.
Now we know the reasons are for maintaining the correct tire pressures on your car, how do we get to the saving money part? Since both overinflation and underinflation will cause premature tire wear, you’ll have to replace your tires more frequently. And have you seen the cost of new tires these days?
If you want a shocker call a tire store and ask for an out-the-door price for the tire size and type for your car (they’ll look it up). In addition to the cost of the tire itself, there’s sales tax, disposal fees, valve stems, and balancing. If the tire comes with a mileage warranty a four-wheel alignment might be required. Some dealers may or may not charge for filling your tires with nitrogen rather than air, which as hocus-pocus as it sounds is actually a good investment (less prone to inflation pressure changes based on the outside temperature).
So here are some tips on making sure you’re riding around on tires at the proper inflation pressure:
- Buy yourself a decent tire pressure gauge from an auto parts store. They’re best able to guide you to a reliable but not too expensive gauge. The accuracy of the pressure gauge at the end of the gas station air house is dubious at best, so best to control your own destiny by keeping the newly-purchased gauge in the glove box.
- Write your tire’s proper inflation pressure on a sticker and slap it on your gauge. You’ll never have hunt around for the recommended tire pressure again.
- Check your tires’ pressures only when they are COLD, which means they haven’t been driven on for at least three hours. If you check when they’re hot, the reading will be higher, you’ll be tempted to let out air, and then the tire will be underinflated when cold again.
- Develop a routine as to when you check your tire pressures. It should be once a month so maybe you pick a payday, lucky number, birth day (i.e. 17th of the month), or some other easy-to-remember date. Enter a reminder into your smartphone so you have no excuses.
Now to the saving the Earth part. Have you ever stood at a busy intersection and noticed a fine gray dust everywhere? That’s rubber coming off tires as they wear. And tires are made of nasty stuff like polyisoprene, carbon black, polystyrene, and styrene-butadiene, and who wants more of that stuff floating around than necessary? So by properly inflating and thus increasing the life of your tires, the less of these chemicals you’re adding to the atmosphere per mile driven.
The other great advantage is in the reduced consumption of fossil fuels. According to Department of Energy data, even a 1 psi improvement in inflation pressure increases MPG by 0.3%. Not much individually, but taken across all drivers in the US that’s nearly one-half million gallons of gasoline wasted and related greenhouse gases pumped into our atmosphere.
Premature tire wear also contributes unnecessarily to giant tire scrap piles. These tire scrap piles can cober hundreds of acres. Each year over 200 million tires are scraped, with only a fraction recycled for other uses. Furthermore they hold water and become a safe haven for mosquitoes. Scrap tire piles can also become a home for snakes and rats. Yuck. Scrap tire piles often burn through natual causes like lightning strikes or intentionally by arsonists. These tire fires are nearly impossible to extinguish and generate extrememly toxic smoke and runoff to waterways.
Now you know all the reasons why a monthly tire inflation pressure check is in your best interest. And all what it takes if for you to take five minutes a month to make sure it happens.
Monstorus Use of Scrap Tires
Sculptors in England have created unique art works from used tires. Unfortunately their use is limited to a few dozen tires while worldwide scrap tire inventories are reaching one billion units.
Tire Fire Creates Huge Plume of Smoke Over Tacoma
The fire started just after 5 p.m. Monday near the 5000 block of 12th Street Northeast near the Port of Tacoma. Firefighters jumped on it right away and they immediately had their hands full – lots of debris, outbuildings, old tires and vehicles were …
Improve Gas Mileage with Properly Inflated Tires
Monique O’Grady with the Alliance to Save Energy discusses the importance of tire air pressure levels and how it can save gas.