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 are putting 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 didn’t have a spare -- something she discovered for 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.”
Still, the trend is gaining traction. A few years ago virtually all new vehicles came with spares, but last month about 13% of the more than 1 million vehicles sold in the U.S. did not offer an extra tire as standard equipment, according to a Times review of vehicle specifications and sales data. Spare tires are not required by federal regulators because they are not 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.
Adding even a 10th of a mile of efficiency to their federal fuel economy tests might allow automakers to reach a number such as 19.5 mpg on a vehicle, which they can then round up to 20 mpg on the window sticker.
“Manufacturers do a lot of little things to squeeze more of the last bits of toothpaste out of the tube. Weight reduction is just one of them, and spare tires are a tempting target,” said Don Edmunds, director of vehicle testing for auto information company Edmunds.com.
Then too, fewer motorists have the need to change tires anymore. Technical improvements have made flats less likely, and when they do occur, drivers increasingly rely on roadside assistance services to take care of the problem.
“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 has been 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 having an extra tire. The sealant kits “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, the tire expert for Consumer Reports magazine.
Petersen said the sealant kits don’t work for a tire that is shredded or suffers a complete blowout, and cannot correct the type of sidewall damage that commonly occurs to low-profile tires driven over pothole-strewn roads. Such damage could leave drivers stranded by the road, 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 because they are built with reinforcement that can support the weight of a car. But run-flat tires are still not a perfect solution. “We hear a lot of complaints about noise, tread life and expense,” he said.
The Continental run-flat tires that come standard on the BMW 328 sedan cost about $190 each at Southern California tire stores but are typically special-order items. The standard version of the Continental tire is about $50 less and is more widely stocked.
Improved technology, of course, means that many motorists will never experience a tire blowout.
In addition to improved tires, tire pressure monitoring systems now come standard on vehicles, warning drivers of low air pressure, leaks and punctures. That prompts people to get tires fixed before damage occurs that can cause a blowout.
“People see the light come on, they pump their tires up and they get them fixed,” and that’s probably contributed to a gradual decline in service calls for flats, Edmunds said.
The improvements to tires has led to a decline in calls to the American Automobile Assn. for flat-tire roadside assistance in recent years, although some evidence shows that the trend could be reversing, if ever so slightly.
In Southern California, where vehicles that don’t come with spare tires are hot sellers, calls to AAA for flat-tire roadside assistance increased 2% last year after declining for many years. Local AAA officials said they did not know the reason for the increase.
Nationally, calls to AAA for flat-tire assistance fell from 4 million in 2006 to 3.6 million in 2010, accounting for about 12% of the organization’s call volume.
Automakers say consumers will have the final say as to whether the spare tire becomes extinct.
“If the customers reject the idea of no spare, we will have to give them a spare,” said Mike O’Brien, Hyundai’s vice president of corporate and product planning. “At the end of the day, they will decide.”
If consumer Marc Meisler is representative of motorists, consider the spare endangered. When he first bought his Elantra, Meisler said, he was chagrined to learn that it had no spare.
“I thought about pulling the spare out of my old Civic and putting it in this car,” the real estate attorney said. “If you have a complete blowout the inflation kit won’t help you.”
Meisler ultimately decided he could live without it, figuring he could always call for roadside assistance.