Dear Tom and Ray:

I have a 2004 Mazda Miata (with rear-wheel drive). Most companies advise me that I need to put snow tires on all four wheels. Is this true for my rear-wheel-drive Miata? Or is this true only for front-wheel-drive cars? -- Mark

RAY: I understand why you're suspicious, Mark. I mean, here's a guy who sells tires for a living advising you to buy four tires instead of two tires. Sounds fishy, right?

TOM: But it IS better to put four snow tires on your car, whether it's front-, rear- or all-wheel drive. In the old days, we used to put only two snow tires on cars, which went on the driven wheels -- the rear wheels, in your case. The idea was that the tires would help you get started and "go" in the snow. Makes sense, right?

RAY: Then people came to a funny realization. That it's ALSO good to be able to "turn" and "stop" in the snow! That's why four snow tires are better.

TOM: It's also a little better to have four of the same tires when there's no snow on the ground. Your handling will be more predictable, particularly in an emergency.

RAY: And many all-wheel-drive vehicles require you to have four identical tires in order to protect the differentials.

TOM: So if money is a serious issue, you CAN go with two snows. You won't do any mechanical damage to your Miata. But when you're sliding on packed snow into, or under, the tailgate of a Ford Expedition, you might wish you had sprung for the other two tires.

If you buy a used car, will you just be inheriting the previous owner's problem? Tom and Ray dispel this and other myths about used cars in their pamphlet "How to Buy a Great Used Car: Secrets Only Your Mechanic Knows." Send $4.75 (check or money order) to Used Car, P.O. Box 536475, Orlando, FL 32853-6475.

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