Testing begins on aftermarket tire sealant kits

In a perfect world, a tire sealant kit may sound like a quick, convenient way to fix a flat tire. No need to remove the tire—just add sealant, inflate, and go. But, it turns out, there is more to it. To better understand the available products, we have begun evaluating several.

Given the promise for an easy roadside repair, the popularity for aftermarket sealant products is understandable. Further, the industry is seeing growth as tire repair kits are increasingly becoming standard equipment on new cars, often replacing the spare with an air compressor and container of sealant to temporarily seal a punctured tire. (Read "How to prepare for driving without a spare tire.")

Automakers say flat tires rarely happen and the spare tire and jack hardware add weight, dragging down fuel economy. Data from Continental, a maker of a popular tire sealant kit, claims consumers experience a flat tire about every 10 years when driving over well-maintained roads. (I just had one, so I must be good for a while!)

Visit our tire buying guide for quick access to the latest advice, tire selector, and Ratings.

Truthfully, we don't like tire sealant products since they are—at best—a temporary or emergency fix and most are useful only for repairing small punctures. These products won't resurrect your flat tire if it has a large puncture, cut, sidewall damage, or ran while flat. Plus, they may impact your tire pressure monitoring system and complicate repairing or replacing a tire.

That said, we're looking at what you can typically get in the aftermarket and bought some samples to try.

These products vary from the simple can of pressurized sealant, typically costing about $7-$10 to fill a regular size tire, to kits with a compressor and sealant costing up to $80. I tend to favor the kits, as the compressor can be used to top-off your tires whenever they need air. The compressors work off the car's 12-volt outlet and have a convenient built-in air gauge. Some even include a lamp for working on a tire at night. All the products purchased have detailed instructions and clearly spell out they are a temporary fix.

We'll be evaluating the ContiComfortKit ($79); Fix-A-Flat Ultimate ($30); Slime Smart Spair ($19); Slime Safety Spair ($40); and AirMan ResQ Pro ($50, not shown in the photo) tire sealant kits. We'll also test the Slime Quick Spair ($10) and Fix-A-Flat ($7) pressurized can products. Prices reflect what we paid, excluding taxes and shipping. Sealant kits are available online and in stores. The pressurized can products are only sold in stores.

Stay tuned to find out if these products can seal the deal or if they're full of hot air.

—Gene Petersen

More from Consumer Reports:
2013 New Car Preview
Best and worst used cars
Complete Ratings for 200 cars and trucks

Consumer Reports has no relationship with any advertisers or sponsors on this website. Copyright © 2007-2013 Consumers Union of U.S., Inc. No reproduction, in whole or in part, without written permission.