IF YOU’RE DRIVING a car made in the last five years and you plan on road tripping home for Thanksgiving this year, make sure you check the trunk before leaving the driveway. There’s no guarantee you’ll find a spare tire should catastrophe strike on the highway.
According to a report released by AAA this morning, more and more vehicles sold in the US are leaving the lot without a spare on board. The synecdoche for roadside assistance has been tracking the spare’s vanishing act for a while now, and reports that run-flat tires or inflator kits have replaced the “Oh no…” feature on 29 million vehicles over the last 10 years. The trend points north: 36 percent of model year 2015 cars were sold without the backup rubber, up from five percent in 2006.
Why is this eminently practical item getting tossed? It’s the fuel economy, stupid. As carmakers struggle to achieve maximum miles per gallon, they’re shaving off anything resembling dead weight to make vehicles lighter. A 50-pound backup system many customers never use is a tempting target, and comes with the added benefit of having more space to dedicated for passenger space or storage.
Automakers make up for the lack of a conventional spare with one of two options. They throw a tire inflator kit in the trunk, so customers can seal punctures and re-inflate their rubber. Or they equip their cars with run-flat tires, designed to stay inflated over limited distances after being punctured.
AAA argues neither’s a great substitute. “We haven’t seen any decline in the calls for road service,” says John Nielsen, AAA’s managing director of automotive engineering and repair. “One way we can look at that data is to say maybe what’s failing on the tires is a catastrophic failure. In those cases, tire inflator kits aren’t going to help.”
In other words, a kit or run-flat may help if you drive over a nail, but if you suffer a blowout, you’re hosed. After testing a variety of commonly found inflator kits, AAA found that they work great as long as you’ve just punctured the surface of the tread and the insidious bit of shrapnel remains in the rubber. Then you can use the kit to coat the inner wall of the tire with sealant before deploying the compressor to re-inflate it. Considering that’s a pretty specific use case, it’s no wonder AAA hasn’t seen a decrease in the requests for flat-related roadside assistance. And it turns out those devices, which have a shelf life of four to eight years, aren’t cheap to operate either.