Tire Pressure: When Too Much In Not Enough and Too Little is Too Much

Last week, Lost in the Tire Department asked me to give her the short and dirty list of things every girl should know on the car-front, or as I call it, “The Top Five Things Every Girl Should Know to Save Her Own Butt (Tire Version).”
I went over how to check your tire pressure step by step, so if you need to refresh your memory, check it out.  This week, I’m going to tell you why maintaining the proper tire pressure is so important.  The first thing you should know about tires is that they are one of the most important safety features on your car, so maintaining them isn’t just important, it’s vital to you and your family.  Let your tire maintenance get away from you and you may be shelling out more hard-earned cash sooner than you want for a new set or you may end up injured (or worse) in an accident.
Tire pressure is the measure of the amount of air in a vehicle’s tires.  Pretty simple, right? Well, so is maintaining the correct pressure.  Each vehicle will have the recommended tire pressure listed in its manual or on the car itself.  The maximum pressure listed on the tire is not the recommended pressure, it’s the amount you shouldn’t go over, and there’s a big difference.  The reason you want your tires to be at the recommended level is that you want the best performance out of them and the longest life.  So, what happens when your tire pressure is too high or too low?

Your car with too much air in the tires...

If your tire pressure is too high, less of your tire will touch the ground or hold the road, and you’ll end up with a bumpier ride.  Now, your kids might enjoy the feeling of being on a roller coaster every day on the way to school, but it’s not safe for you, for them, or for your wardrobe.  Extra bumps mean extra spills, girls.  You know you stop every morning on the way into work for your Starbucks, Dunkin Donuts, etc.  Keep that pressure too high in your tires and you’ll be wearing your coffee by the time you reach the office.  Even worse than your drying cleaning bill or extra laundry is the fact that when less of your tire meets the road, you have less traction and stopping distances suffer.  You’ll need more time to avoid that car in front of you that slammed on its brakes, but will you get it?  Not if your tire pressure is too high.

Now, if the pressure is too low, you’ve also got a problem. When the pressure in your tires is too low, more of the tire’s surface area is touching the ground and creating friction (and heat).  All that extra friction can make your tires wear out before their time and possibly overheat.  Do you know what happens when tires overheat?  The tread can separate and you can find yourself in a very nasty accident or stranded on the side of the Billy Graham Parkway in Charlotte because some divine force took pity on your stubborn behind and made you pull over to check that disturbance in your tire force before you killed someone else or yourself.  (Thank you, Billy Graham!)  What will you do if this happens to you and your highway is not so particularly blessed?  Let’s not find out.  Check your tire pressure!  One easy sign that your tire pressure may be too low is this:  When you turn a corner, your tires squeal.  That’s only cool in the movies, so check it before you wreck it.

Don’t just wait until you suspect a leak to check the pressure either.  Did you know that tire pressure changes with the temperature?  If the last time you checked your tires it was 85 degrees in July, and now it’s minus 10 in February (hello Minnesota!), then your tires could have lost a significant amount of pressure.  Here’s a little math fact for you: Tire pressure decreases by about 1 pound per square inch for every 10-degree drop in outside air temperature.  Get your calculator out if you need to, but check your pressure just to be safe.  As my grandmother would say, “Better safe than sorry, girl!”  Another option if you want to avoid a math problem is nitrogen.  A lot of folks are discovering the benefits of running nitrogen tire inflation. When you increase the nitrogen level in the tire above 95%, it runs cooler.  The molecules in nitrogen do not seep out of the tire the way oxygen molecules do, so the ultimate benefit is losing less air than normal and checking your pressure less often.  (P.S. Many people have reported slightly better fuel economy using nitrogen fill, too!)  Nitrogen needs its own post, actually, so keep your eyes on this column for all the scoop on nitrogen tire inflation!  It’s coming soon!

Next time, I’ll tell you how to figure out when to buy new tires.  In the meantime, if you have questions, run on into your local RNR.  They’ll answer every question you can come up with and tell you things you never even thought to ask.  Talk to you soon!

Bree