by Pat Goss
PAT GOSS: Critical to a safe and economical car are our tires, and here to give us some basic tips is Bob Toth, he’s a tire engineer. Welcome to Goss’ Garage.
BOB TOTH: It’s wonderful to be here, thanks for having me.
GOSS: Okay Bob, one of the common questions that we get concerns tire pressure. What is the proper tire pressure for my car?
TOTH: Well most importantly everyone should remember that tires are four of the most important and least understood components on your car regardless of what you drive, and fundamental to that tire’s performance is the inflation pressure. You should check that inflation pressure at least once a month, and think about this, the inflation pressure is important because it helps determine how well your tires stop, start, and corner but also how much fuel efficiency they deliver. The U.S. Department of Energy says that over 3.5 million gallons of fuel is wasted each day due to under-inflated tires, that’s over a billion-dollars a day in today’s gas prices.
GOSS: That’s a lot of money!
TOTH: A lot of money!
GOSS: Okay, but where do we find the proper pressure?
TOTH: To find the most appropriate inflation pressure for your vehicle you should go to the glove box and look at the owner’s manual or often on the inside of the glove box there’s actually a placard. On some vehicles the door-jam has that placard, or the gas cap lid. The important thing to remember is don’t go to the sidewall of your tires, on the sidewall of the tires that inflation pressure is max inflation pressure for max load, you should always go to the vehicle manufactured inflation pressure
GOSS: Okay and that means we need a tire gauge and of course we have the traditional pencil gauge that everyone is familiar with which is okay but the 89-cent version?
TOTH: These are fine as long as you get a quality, properly calibrated one. You should keep that in your glove box in fact and check your inflation pressure at least once a month.
GOSS: All right now here we have a dial-type gauge which are known to be more accurate but they cost more money and…
TOTH: Much better. A little more inconvenient, typically you don’t want to carry this thing around in you glove box, you’ll have it in the trunk which makes it a little harder to get to. Another important way to check your inflation pressure is to stop by your local tire retailer. Typically it doesn’t even matter what brand of tires you have, they’ll be happy to check the inflation pressure of your tires and then air them up at no charge.
GOSS: Okay, now wear, that’s another big issue. When do I have to replace my tires?
TOTH: Ah, tread-wear. Inspect those tires at least every two months for sure. Inspect them for unusual wear and one way to check the wear on your tires is to simply use a Lincoln head penny; turn Mr. Lincoln upside down, bend down, put Lincoln’s head upside down into the groove, if you can see all of Mr. Lincoln’s head then your tires are legally worn out - that’s 2/32 of an inch. If part of Mr. Lincoln’s head is covered then your tires still have some wear. Now to add a little bit of a safety margin you could use the George Washington quarter rule, that will provide you a measure of 4/32 of an inch, that tells you when you’ve got 2/32 to go before the tires are legally worn out, gives you a little measure of safety.
GOSS: Yeah and that’s an important fact.
GOSS: Bob thank you so much
TOTH: You’re certainly welcome.
If you have a question or comment, write to me or send me a DVD video of your question and you might see yourself on TV.
The address is MotorWeek, Owings Mills, MD, 21117.