All-wheel drive has evolved rapidly since the old days when Audi and Subaru were the only two automakers embracing this important technology. There are now a variety of AWD systems to choose from. Let’s break it down and find out what type suits your individual needs.
In the modern U.S. market, the first car to have some way of driving all four wheels was the 1980 AMC Eagle. The general idea of making cars better in the snow happened in all the major world car markets at about that same time. Subaru and Audi took the idea of all-wheel drive (AWD) and made it a part of their brand identity, something that continues to this day. AWD is heavily marketed by automakers as a safety feature. It is debatable whether this is true, but as we explain later in the story, there is fact-based data to support the idea that AWD drive vehicles are safer. The great news for those considering AWD is that all the systems work. The differences lie in what the AWD car is trying to accomplish. Let’s check out the different styles of AWD.
AWD – Family Vehicles
Family vehicles like minivans, crossovers, and affordable sedans all use a front-wheel drive (FWD) vehicle adapted to also drive the rear wheels. Front wheel drive vehicles are already the best type for wet or snowy driving. The advantage lies in the weight distribution. FWD vehicles benefit from having the heavy engine over the wheels that are pulling the vehicle along. That weight helps with traction. Automakers use a mechanical system along with sophisticated software to provide some power to the rear wheels. Almost always, the power is primarily to the front wheels and only sent back after the vehicle’s sensors detect that the front wheels are slipping. Traction control, which can brake an individual front wheel, also reduces power if necessary and works in tandem with the AWD system to smooth out the power delivery.
In this type of design, the main advantage of AWD is to move the car forward when starting off. Some vehicles in the family-vehicle class can provide more power to individual rear wheels, but the effect is minimal. Our test driving has never revealed any significant advantage to “torque vectoring AWD” in family cars driven at legal speeds. The best part about the AWD in family vehicles is that it is totally automatic. Some vehicles do add a drive mode such as a “Snow” setting. These types of systems generally just reduce power and start the vehicle off in second gear rather than first. Toyota was a pioneer of this type of “Snow Mode.” One thing to be aware of is that AWD does not help you stop. Ever. And it does almost nothing to help you turn in snowy conditions. To make your car better at turning and stopping add snow tires. We compared a Subaru Impreza with its standard all-season tires to a very similar Mazda3 with front wheel drive and snow tires last year. Overall, the two-wheel drive Mazda3 on winter tires was much better in the snow.
AWD – Crossovers and SUVs
Crossovers and SUVs try hard to distinguish themselves from other vehicle types and from one another by claiming that their AWD system is the best. While we won’t dive into that fight, our opinion is that for on-road use in snow AWD is a huge advantage. Which company you choose is a matter of taste. What does matter is tires. We tested an AWD Jeep Cherokee with standard Firestone AWD tires against a Toyota Highlander (2007) with Bridgestone Blizzak winter tires this past winter in snow and were shocked by how well the Cherokee did. Looking closely at the Cherokee’s Firestones, we could see that the tire maker added more than the usual amount of winter technology to the tire. This only reinforces our belief that winter tires are important. Yes, some automakers do equip their crossovers and SUVs with great AWD tires, but for the best traction, get AWD and winter rubber.
Our recommendation is, for normal driving, avoid SUVs with “four-wheel drive (4WD).” 4WD is mainly for towing, plowing, and off-road use. Beware of part-time systems that are labeled 4L, 4H, and 2H. This is not the best setup for commuting and routine driving.
AWD – Sports Cars and Premium Cars
Sports cars and sports sedans take a different approach to AWD. Many start with a rear-drive vehicle that has been adapted to send some of the power to the front wheels. Generally, these vehicles are mainly rear-drive and send part of their power forward only when they detect slippage. We have tested a few that actually will spin their rear wheels for an instant on wet roads before their AWD system catches up. True sports cars are rear-wheel drive. There are benefits to that setup. However, more and more automakers are equipping their sports sedans with AWD. Lexus for example for many years would not even ship an IS 250 sports sedan to northern markets without AWD.
Rear drive cars with performance tires are terrible in the snow compared to family cars. The size and shape of sports car and sports sedan tires and rims work against good snow traction. AWD sports cars and sporty sedans add AWD to make them more rounded and to make them viable for 4-season driving. Buyers may notice that on AWD models, the automaker will change the tire sizes on the AWD versions of its cars so that they are more winter-capable. We would not recommend a sporty car to people who plan to drive in winter conditions a lot. However, for those that need the car on rare occasions in the winter, this setup will work. Still, snow tires are a must.
Sports cars break the rule about AWD not being able to help turn a car. The special AWD systems they employ can actually help to make the car rotate, particularly when the car is being accelerated. This ability should not be confused with helping you to turn off a busy street onto your side street near home in a snow storm. You will be travelling at slow speeds and tires will be the limiting factor. Do not be swayed by marketing pitches that try to tell you that AWD will help you to maneuver in snow.
Finally, there are some sports cars that use AWD just because they are so powerful they cannot put all that power down without providing power to all four wheels. Examples include Some Audi RS models and cars like Lamborghinis.
Many auto writers point out that snow tires are the most important part of winter safety. Though true, the Insurance Institute For Highway Safety keeps track of the death rate in all mainstream automobiles. AWD versions of the same model show a decided advantage. In fact, of the nine vehicles that showed zero driver deaths over a three-year period, seven of the nine could power all four wheels. AWD is not the final word on vehicle safety, but its role in reducing deaths is proven by statistics.
If you are considering an AWD vehicle keep in mind that the first consideration should be the type of driving you will do. AWD will help you no matter which vehicle type you choose, but if you are interested in the best winter performance possible choose a family vehicle with AWD and don’t forget to add snow tires.