Helping tires get a grip

The claims

Tyre Grip creates a "better grip on snow, ice, and slush" by providing "an adhesive surface that grips the roads." You spray it on tires, and it's supposed to work for up to 50 miles per application. We bought a can for $24.95 (later we saw a newer, blue can for $19.95). A second product, AutoSock, is a cloth and mesh cover you slip over a tire and wheel. It "clings to snow and ice, increasing vehicle traction," and is designed to be used at speeds of 30 mph or less. We paid $99 plus shipping for a pair of AutoSocks. They come in different sizes, to fit most cars.

The checks

We sprayed Tyre Grip on the tire tread of a Honda Accord's front drive wheels, then did acceleration and braking tests on a snowy road in Vermont. We also drove up a small, snowy hill using the Accord's all-season tires alone, using Tyre Grip, then using AutoSock over the front wheels.

Bottom line

Don't toss your snow tires. Tyre Grip improved traction modestly during acceleration and braking, but any benefit waned after about one mile. On our hill, Tyre Grip improved starting traction slightly, but the Accord couldn't reach the top with or without the spray. With AutoSocks over the front tires, however, the car summitted many times. It could be a good tool to keep in your car just in case. The downside: AutoSocks are very cumbersome to slip over tires (expect to get dirty and wet), and they're meant to be used only on snow or ice and to be removed immediately when the road becomes clear.