Do You Need Snow Tires Or Chains With AWD?

Tire chains are typically used during extreme winter weather conditions, and depending where you drive, you might need them to be installed on or carried in your vehicle. Tire chains can be made of either actual chain or metal cables that perform the same function. These chains wrap around the circumference of your tires and can dig into deep snow and generate grip in situations where even winter/snow tires may not be able to get any traction. State authorities typically monitor winter weather conditions and notify motorists whenever snow/winter tires and/or chains need to be used in a given area.

For example, the state of California has three levels of requirements — chains are required on all vehicles (R3), chains (or one of these tire chain alternatives) are required on all vehicles except for AWD/4WD vehicles with winter/snow tires on all wheels (R2), and chains are required on all vehicles except those under 6,000 lbs. gross weight with snow tires on two drive wheels (R1). Chains must still be carried in your vehicle during R1 and R2 conditions. Check the specific regulations for the state where you will be traveling — most states have similar provisions allowing drivers of AWD or 4WD vehicles with snow tires to drive without tire chains.

Here's a sobering statistic: Of all auto accidents related to weather conditions, 41% happened in winter when ice, snow, slush, or sleet were present. Since your vehicle's only contact with the road is through its four tire contact patches, snow/winter tires or chains can make a big difference. Snow tires (also known as winter tires) are not the same as all-season tires. Where all-season tires are designed for a wide combination of weather conditions ranging from completely dry to rainy to minimal amounts of snow, winter tires have a much more specific mission. 

Winter tires not only have a more aggressive tread pattern designed to bite into snow and provide improved traction, but their softer rubber compounds are also made to grip the snow and ice on the road, allowing them to keep you safe in colder environments. Once you have tried winter tires in serious snowy or icy conditions, you won't want to be without them. When using tire chains on AWD vehicles, they should be used on all four wheels. Since the AWD system uses all of the wheels to give you stability and traction, chains on all wheels even out the grip levels and transfer your vehicle's AWD strengths to the wintry road conditions. When the roads clear, you are required to remove your chains.

AWD is designed for use on the road. It provides traction to all four wheels and distributes that traction to each wheel based on how much grip it is getting at any given moment. This works fine under normal conditions (namely dry, wet or light snow-covered roads) with the all-season or summer performance tires that most vehicles come equipped with. But what happens when conditions worsen and you have to deal with a heavy snowfall or an ice storm? Even if you have one of the  best AWD systems out there, the frozen precipitation building up on the road does not play well with your all-season or summer tires. Their narrow tread grooves fill up with snow, their warm-weather tread compounds harden, and there is not much grip to be had. 

Minimal traction means that you are literally spinning your wheels and not going anywhere. Regardless of what your AWD may be capable of, your vehicle's limiting factor is now its tires. In most states, you'll need tire chains or snow tires on your AWD vehicle. Consumer Reports performed an independent test, showing that a front-wheel drive vehicle with four winter tires performed much better than an AWD vehicle on all-season tires in winter conditions. Check with the motor vehicle agency or state police where you live to see what the tire chain regulations are, but it's a safe bet that unless you have winter tires, you'll need to at least carry a set of chains with you in the winter.