Tire Chain Information

Tire chains can be one of the best ways to make a vehicle perform under extreme conditions, giving added traction on a variety of surfaces. But there are also significant drawbacks to using tire chains. Several alternatives should also be considered before the decision to use chains is made, and when chains are necessary, they must be used properly for maximum effect.

Tire Chain Basics

Tire chains work by attaching around the tread portion of a vehicle's tires. The strips of chain act much like the tire's original rubber tread, except on a larger scale. Chains can be useful in snowy, icy or muddy conditions where traction is difficult to attain by the tire tread alone.
In cases where "all weather" or "all season" tires are being used, the tread is generally meant to provide traction on dry (or slightly wet) pavement, and was never intended to propel a vehicle under harsh conditions. Chains can be attached and removed relatively quickly (more quickly than changing a vehicle's tires or wheels), and thus, provide an extra dose of traction at times when it is most needed. For many long-distance truckers, tire chains are part of their standard package of driving tools. They are also useful for anyone whose environment is subject to harsh weather, or where roads are not well maintained.

Proper Tire Chain Use

Tire chains work best when they are applied following the manufacturer's instructions. This process usually involves attaching the chains and then tightening using a tensioner so that they fit snugly over the tire. Chains must be appropriate for the size of the tire to which they are being attached, and the tire must be at its recommended inflation to ensure a good fit.
Tire chains are placed on a vehicle's drive wheels, and so must be used in matching pairs. In the case of vehicles with all-wheel drive, chains can be attached to all four wheels, or to either pair (front or rear). Placing chains on the front wheels of a vehicle with all-wheel drive can help in braking and steering, while placing chains on the rear wheels only generally helps with maintaining traction.

Requirements and Restrictions

The Society of Automotive Engineers (SAE) specifies three classes of tire chains. These classes are based on the amount of space between the wheel and the vehicle itself, which determines how much room there is for a chain and what size chains are to be used. Class W chains are intended for vehicles with at least 2.5 inches of space vertically and 1.5 inches of sidewall clearance. These specfications are reduced to 1.97 inches and .91 inches for Class U chains and 1.46 inches and .59 inches for Class S chains.
Before using tire chains, it is also important to be aware of local regulations that may govern their use. Some streets may only allow vehicles with chains during certain parts of the year, or when a special status determined by the weather has been proclaimed. In some cases, tire chain use is prohibited altogether. Conversely, some roads allow only vehicles with chains due to the likelihood of regular tires causing drivers to be stranded.

Disadvantages

The main disadvantage to using tire chains, besides the need to take time to attach and remove the chains from the vehicle's tires, is the extra wear imparted onto road surfaces. Paved segments that receive heavy traffic from vehicles using tire chains, such as roads that ice over frequently, yet are part of major shipping or transportation routes, may need to be serviced or repaved far more frequently than roads that are not trafficked by tire chains.
Tire chains also limit the safe speed at which a vehicle can travel. Most chain manufacturers suggest driving no faster than 30 mph when chains are installed. Chains may also become loose if they are used for an extended period, necessitating frequent stops to reposition or tighten the chains. When chains are placed on many wheels, such as in the case of a large truck, the expense of chains can also be considerable.

Tire Chain Alternatives

There are several alternatives to using tire chains that may be simpler, more cost effective or less damaging to road surfaces. Snow tires or all terrain tires are standard rubber tires with special tread patterns that are intended to work even under less-than-ideal conditions. In a seasonal climate where snow is common but not constant, these sort of tires are included on most new vehicles, and should be enough to allow for safe driving in most situations. Placing snow tires on the vehicle's drive wheels (and, in the case of rear-wheel drive cars and trucks, placing extra weight over the drive wheels by storing sand, gravel or cinder blocks in the trunk) can prevent a vehicle from becoming stuck in snow or mud.
Studded tires, some of which feature screw-in metal studs, give drivers an extra measure of traction for especially harsh conditions. Fabric chains, sometimes called socks, can also be used to perform a lesser version of the same function as traditional metal chains.

References

• Edmunds - Install TIre Chains
• Tire Chains for Winter Use

Resources

• Tire Chains