Am I over-inflating my tires if I put in the maximum allowable psi of air?

Dear Car Talk

Dear Car Talk | Apr 01, 1995

Dear Tom and Ray:

I have the following tires on my 1994 Caprice Classic: Eagle GA Touring 235-70R15. When I had battery trouble, the tow truck driver told me to always put in the maximum pressure listed on the tire, which is 44 psi. At my service station, the guy told me to never put in more than 35psi. Who's right?

RAY: Even though there are three tow truck drivers serving as top advisors to President Clinton on matters of sub-atomic partical acceleration theory, I don't think this particular guy gave you very good advice, Earl.

TOM: 44 pounds per square inch (psi) is the maximum ALLOWABLE pressure. Any more than that, and the tire could blow up! That's different from the "recommended" pressure, which is probably 35psi or less.

RAY: It's like speed, Earl. The maximum speed of your car may be 110 miles per hour. But nobody recommends you DRIVE it 110 miles an hour. The "recommended" speed may be 55 miles per hour.

TOM: If your tires are the same size as your original tires, you should follow the manufacturer's recommendation for tire inflation. That inflation number is usually posted on the inside pillar of the driver's door or inside the glove box.

RAY: Over-inflating your tires can be dangerous. It gives you poorer handling and poorer braking, not to mention faster, and more uneven tire wear. So listen to the manufacturer, Earl. By recommending a ridiculously high tire pressure to you, that tow truck driver may have just been trying to drum up future towing business.....yours!

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