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My question is in regard to proper tire pressure When...

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Dear Tom and Ray:



My question is in regard to proper tire pressure. When you buy a new car, the owner's manual tells you to abide by the sticker inside the door post. My present car calls for 30 psi in all four tires. But when I get the car back from the dealer, the tires generally have 36-38 psi. Do they know something I don't? -- Howard

RAY: No, you apparently know something they don't, Howard. Either their equipment is inaccurate, or they're just being careless.

TOM: Or perhaps, after the Firestone tread-separation debacle, they're so afraid of underinflating tires that they're being overzealous and overinflating them.

RAY: But you're absolutely right, Howard. If you have the original tires on your car, or approved replacements that are the same size, then the pressure recommendation in the owner's manual (or on the door post) is the one to follow.

TOM: Just be sure YOUR measurements are accurate. You have to use a good-quality tire gauge. We recommend the round gauges with the needle, rather than the "pencil" type gauges with the pop-up indicator.

RAY: And be sure you're measuring the pressure when the tires are relatively cool, since heat from driving can dramatically increase the pressure. So if you take a 30-minute drive home from the dealer -- including a jaunt on the highway -- and then hop out of the car and measure the pressure, it's likely to be inflated by the heat generated during the drive, and it will give you an inaccurate reading.

TOM: But if you're checking the pressure with a good gauge when the tires are cool, you have every right to ask the guys at the dealership (nicely) to shape up and be a little more careful from now on.
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