The proliferation of all-season tires and all-wheel-drive platforms in recent years has caused owners who live in snowy parts of the country to think twice before spending money on winter tires. If you have purchased a new vehicle within the last several decades, chances are that it was factory-equipped with all-season tires. (Only a relatively few high-performance machines come standard with summer tires.) All-wheel-drive, once limited to trucks, has now found its way as standard or optional equipment for just about every SUV for sale, as well as many mainstream sedans. Let's begin our discussion about the case for winter tires by looking at the history of how these two technologies became so widespread.
Fifty years ago, the tire industry offered 'regular tires' for regular drivers, and snow tires for people who drove in the snow. Passenger car tires were of bias-ply construction; just a few import brands were installing radials. Only farmers and blue-collar professionals drove 'trucks' as daily transportation, and they had truck tires on them. With 99% of the cars in America powered by rear-wheel-drive systems, snow tires, if used, were bought in pairs and mounted only on the rear. If you needed additional traction, you bought studs or snow chains. If you were frugal, you threw several bags of sand in the trunk.
The final three decades of the 20th century is when things started to change in a big way. There was a drivetrain revolution, with front-wheel-drive charging forward to become the predominant set-up for cars. The engine sitting over the drive wheels provided a tremendous traction advantage, as engine weight pushed down on the rubber, helping to minimize spinning and skidding. These car owners wondered if they still needed snow tires with this extra traction. But they didn't necessarily have better steering or braking in the slippery stuff.
"All-Season" Tires
In the late 1970s, the tire industry developed a compromise, when the first "all-season" tires were introduced. Billed as a tire that offered summer quiet and comfort, with winter traction and grip, auto manufacturers saw it as a way to advertise the end of seasonal tire swaps. But note the use of the word 'compromise', as that is just what an all-season tire is: better than a snow tire in the summer, and better than a regular tire in the winter, but not as good as a tire purposely designed for hot- or cold-weather conditions.
After passenger cars switched over to front-wheel drive in the '70s and '80s, the SUV craze came along in the '90s. Truck-based four-wheel-drive systems had long been available, but primarily for commercial drivers or hard-core off-roaders. Manual locking hubs required a driver to step out into less-than-ideal conditions to engage 4WD.
When Ford (with the Explorer) and Jeep (with the Grand Cherokee) introduced the first modern sport-utility vehicles, with unitized construction, raised riding height, and automatic power delivery to all four wheels, owners were delighted. These and similar other vehicles took off in the marketplace.
Consumers could now purchase improved versions of the old family station wagon, but this time with seemingly unlimited traction. The traction advantages helped get you moving, but didn't offer any help in turning or stopping. Factory-installed tires were all-season or light-truck, but were not maximized for use on snow and ice.
Looking back, it is obvious why vehicle owners were led to think that snow tires were no longer needed. All-season tires on all-wheel-drive platforms got drivers through some conditions which would have stopped a bias-ply-tired rear-wheel-drive car in its tracks. Yet those living in the snowiest climes still needed more than what all-season rubber and AWD could offer.
"Snow" Tires
Tire engineers were not sitting on their hands during all this. They were working on ways to improve the snow tire. Better, grippier, tread patterns were developed as were rubber compounds optimized for very low temperatures. These advancements were significant enough for the industry to change the category name from "snow tires" to "winter tires".
The new name indicates that these new designs aren't just for snow; they are actually designed to work on all different types of winter driving surfaces, and in winter temperatures. The reformulated rubber compounds stay more flexible in sub-freezing temperatures, providing more grip, even on ice. The aggressive new tread patterns dig into the deepest snow but aren't unbearably noisy on dry pavement.
This is the bottom line: all-season tires and all-wheel-drive powertrains help with winter driving, primarily to gain and keep traction. But neither of these technologies help much, if at all, with steering (maintaining directional control) and braking (stopping without sliding). A dedicated set of winter tires, with optimized tread patterns and cold-weather rubber compounds, mounted at all four corners, offers even more traction, AND provides steering and braking control in the slippery stuff that simply isn't offered by all-season tires or AWD.
If you live in a part of the country where the possibility of regular snowfall exists (enough to shovel or plow), and you need to be on the road, the only way to go (and steer and stop) is by using a set of four winter tires!