Dear Tom and Ray:

What's with those tiny doughnut spare tires the auto salespeople want to foist on us these days? Recently, one of my tires blew and shredded on an interstate. I was able to put on the doughnut and drive to the next town 15 miles away but found no replacement tire there. A nice guy at one of the gas stations warned me to drive slowly and not to go farther than 50 miles or I'd ruin my transmission. The next town was 40 miles away! Now I'm thinking of buying a new car, and I don't want to pay for one of those doughnut spares that makes me mad every time I see it in the trunk. What are my options? - GeorgeTOM: Great questions, George. As you probably know, these "doughnut," or miniature spares, came into fashion in the '70s when cars were being downsized. Carmakers were looking frantically for ways to save space, weight and, of course, money.

RAY: Minispares made sense for a number of reasons. Since tire technology was better, people were getting fewer flat tires, so spares were used much more - shall we say - "sparingly." It also occurred to carmakers that a spare didn't have to be a permanent replacement but could be designed for temporary, emergency use.

TOM: And since 99 percent of flat tires occur within 50 miles of a gas station (as does most human activity in the United States), the minispares actually work fine in most situations. They're not designed for speeds of more than 50 mph or more than 50 miles, not because transmission damage will occur, but because they're really junk and can't take the stress normal tires are subjected to.

RAY: As for your options, they're getting slimmer. According to our Access Dynamics AutoNet automotive database, fewer and fewer new cars are offering full-size spares as standard or even optional equipment these days. A few popular cars that DO offer them as options are the Chrysler minivans, the Ford Taurus, the Toyota Camry and the Dodge Spirit/Plymouth Acclaim. Many sport utility vehicles and luxury cars (and a few surprises, like the Yugo GV) come with full-size spares as standard equipment.

TOM: Of course, making a full-size spare available as a dealer-installed option simply means there's enough room to store one in the spare-tire compartment in the trunk. If your mother-in-law is willing to ride in the back with the Labrador retriever and a P205 radial on her lap, you can have a full-size spare in any car you want, George.

Dear Tom and Ray: What's the difference between a "demo" and a "used" car? - Warren

TOM: A demo has been ruined by hundreds of different people who are thinking about possibly buying it.

RAY: A used car has been ruined by only one or two people.

Got a question about cars? Write to Click and Clack Talk Cars c/o King Features Syndicate, 235 E. 45th St., New York, NY 10017.