Snow chains

Snow chains, or tire chains, are devices which are affixed to the tires of vehicles to provide superior traction when driving through snow and ice. Snow chains are usually attached to the drive wheels of a vehicle (e.g. the front wheels on a front-wheel drive car), though all four wheels should be chained to provide extra stability. Some owner's manuals for four-wheel drive cars specify that two specific wheels can be chained, leaving the other two unchained if necessary.

Snow chains are sold as paired sets of two. You should buy chains that match your tire size (tire width and radius numbers can be found printed on the tire).

A set of chains are placed on the wheels that are connected to the drive train in order to gain traction in icy, snowy or muddy conditions.

Front Wheel Drive Vehicles: Most passenger cars are front wheel powered vehicles, so the snow chains would be placed on the two front tires. (Though all four wheels should be chained to provide extra stability as long as the vehicle's owner's manual does not indicate chains cannot be used on all four wheels.)

Rear Wheel Drive Vehicles: Pickup trucks, older cars and sporty cars are usually rear wheeled drive so the chains are placed on the rear tires. (Though all four wheels should be chained to provide extra stability as long as the vehicle's owner's manual does not indicate chains cannot be used on all four wheels.)

Four Wheel Drive Vehicles: Four wheel vehicles can use two pairs of chains to cover all four wheels. With only one pair of chains they are often put on the rear wheels, but can be placed on the front wheels instead for the added steering and braking benefit. (All four wheels should be chained to provide extra stability as long as the vehicle's owner's manual does not indicate chains cannot be used on all four wheels.)

In snowy conditions, transportation authorities often require snow chains to be fitted on vehicles that lack four-wheel drive and proper tires. These requirements are usually enforced by checkpoints, before which eligible drivers must have snow-chains fitted on their cars. Near such checkpoints, chains can often be fitted professionally for a fee. Snow chains limit the speed of the automobile to approximately 30 mph (50 km/h), and reduce fuel efficiency.