A tire repair kit includes a compressor that is powered by an electrical cord connected to the car's 12-volt outlet.
The compressor pumps air and liquid latex sealant into the tire, which is re-inflated in five to 10 minutes. Such repair kits typically cost $40 to $100 in the aftermarket.
They have drawbacks:
- The sealant can damage sensors inside some tires.
- The motorist has to buy a new kit to replace the used sealant.
- Repair kits provide only a temporary fix. The motorist must take the tire to a shop for a permanent repair as soon as possible.
Despite their flaws, tire repair kits are eclipsing run-flat tires as a leading candidate to make spare tires obsolete.
Run-flats were introduced in the 1990s, and once were considered a leading candidate to eliminate the spare. The most popular type is the SSR, or the self-supporting run-flat tire. After a puncture, rubber inserts inside the tire reinforce the sidewall, maintaining the tire's shape and allowing the motorist to continue driving at a reduced speed.
Typically, the motorist can drive on it up to 50 miles or so before taking it to a repair shop.
BMW AG installs run-flats on a variety of models, but mass-market automakers seem reluctant to follow suit. Honda Motor Co., for example, no longer uses run-flats on the Odyssey minivan or the Acura RL.
Part of the problem is cost. Replacement run-flats can cost more than $200 apiece, compared with $100 or so for a good conventional tire.
Run-flats often have higher rolling resistance than ordinary tires, and they sometimes wear out quickly.
According to Edmunds.com, only 29 U.S. models sold in the 2012 model year had run-flat tires as original equipment.
While that's more than in 2007, when only 16 models had them, Montoya of Edmunds.com says run-flats have been relegated to a niche market.
"You only see run-flats on luxury cars and sports cars," Montoya said. "We expect to see more tire repair kits" in the future.