Dear Tom and Ray:

My wife just bought a 2013 Kia Soul, and there is no spare tire. The salesman told us that spare tires are becoming a thing of the past. There is a small unit for putting air in the tire in case of a flat. I was just wondering, why no spare tire? What would you suggest?

-- Bill

RAY: I would suggest not driving behind any nail trucks, Bill.

TOM: There are a number of reasons we're seeing more and more carmakers ditch the traditional spare tire.

RAY: The first has to do with fuel economy. A spare tire adds weight. A tire-and-wheel combination easily can add 50 pounds to the weight of a car. And since every pound you carry decreases your mileage, getting rid of that spare is an easy way to get more miles per gallon.

TOM: A second reason is space. With fuel-economy concerns leading to smaller cars, making room for an extra wheel and tire is increasingly inconvenient. Most people would rather have that room for groceries, dogs or that giant heirloom Henry XVI Nose Hair Tweezer they found at a garage sale.

RAY: And then on the other side of the equation is the decreasing need for a spare tire. Flat tires are a lot less common than they used to be. Oh, they still happen. But they used to be very common. With modern tires, it's a very infrequent event for most people.

TOM: There also are other options now. There's the mini-spare (which will let you travel up to 50 miles or so), the auxiliary pump and can of Fix-A-Flat (which will work for things like nails and small punctures) and, if all else fails, there's the cellphone and credit card (which works for pretty much everything).

RAY: Those alternatives are not as failsafe as a real, full-size spare that's checked regularly and kept fully inflated. But carmakers believe that many people would rather have the space and the additional fuel economy these days and just use a temporary spare or call for help if and when they ever need it.

TOM: Of course, if you're someone who drives in remote areas, on unimproved roads or in places that are out of cellphone reach, you may very well want to consider that when buying a car and make sure there is a real spare tire you can opt for. Or you may just decide to buy an extra wheel and tire and carry it in your trunk.

RAY: But for most people, especially those in populated areas, the cost-benefit equation has been pushing the full-size spare tire out of the car for years. And now, at least a couple of manufacturers have decided that even a mini-spare is not worth making room for. Maybe those cars should come with a factory-installed cellphone in the old spare-tire well?