That spare tire in your trunk may be going the way of the typewriter and transistor radio. Automakers are selling more cars without an extra wheel to trim weight, boost gas mileage and shave a few bucks off their costs.
What happens if you get a flat? Some manufacturers equip cars with run-flat tires, while others put flat-repair kits in the trunk. Both alternatives have drawbacks, and many motorists say the trend is unsettling.
"I like the security of having a spare. It gives you peace of mind," said Mary Beth Wasmer of Baltimore.
Wasmer said she probably would have passed on the used BMW 335 she bought three months ago if the dealer had said it had no spare — something she discovered herself.
"I couldn't find it," she said. "I opened the trunk, I looked underneath, and there was no spare or even a compartment to put one in."
The trend is gaining traction. A few years ago, virtually all new cars had spares. But last month, about 13 percent of the more than 1 million vehicles sold in the United States did not offer a spare as standard equipment, according to a Los Angeles Times review of vehicle specifications and sales data. Federal regulators don't require spares because they aren't considered an essential safety feature.
The no-spare club includes the Hyundai Elantra and Chevrolet's Cruze and Malibu, three of America's top-selling sedans. Buick's 2012 Regal GS and upcoming hybrid versions of its Regal and LaCrosse sedans will be sans spare, as will some versions of next year's Kia Optima.
Automakers save money by selling cars with four tires instead of five, and the weight savings helps them boost vehicle gas mileage.
Then, too, fewer motorists need to change tires anymore. Technical improvements have made flats less likely, and when they do occur, drivers increasingly rely on roadside assistance services.
"All manufacturers are looking at this," said Alan Batey, U.S. vice president of Chevrolet sales and service. "This is one opportunity to get weight out of vehicles and make them more fuel-efficient. . . . It will take some time for people to understand this technology."
Chevrolet is among the most aggressive of the major brands when it comes to scuttling the spare. The tire inflator kit in the Cruze sheds 26 pounds of spare tire and hardware and provides more trunk space.
Hyundai said ditching the spare saves it about $22 a vehicle. That adds up to about $4.4 million on the 200,000 Elantras it expects to sell this year.
Like Chevy and Buick, Hyundai sells cars with tire-inflation kits. These consist of a can of sealant that is injected through the valve stem, plugging the puncture, and an electric pump to reinflate the tire.
It's not as good as a spare. Sealants "work only if you have a simple puncture in the tread of the tire. And if you use it, it is only a temporary fix," said Eugene Petersen, tire expert for Consumer Reports magazine.
And sealants don't work for sidewall damage that commonly occurs to low-profile tires driven over pothole-strewn roads. Drivers could be left stranded, waiting for a tow.
More expensive cars — including nearly the entire BMW lineup — are forsaking spare tires for run-flat tires, which can be driven at moderate speeds for 50 miles or so with a puncture.
Petersen said there's less risk of being stranded by punctures in run-flat tires, but they're still not a perfect solution. "We hear a lot of complaints about noise, tread life and expense," he said.