Each winter, we get the same comment from customers, friends and neighbors: they have no need for snow tires since they have a Subaru with All-Wheel Drive (AWD). As they prepare to drive to the mountain for skiing or to travel over a snowy mountain pass, we worry that they are not as well equipped to handle the winter snow and ice as they think.
In the interest of safety, we want to clarify this misconception for our customers and other drivers. The main benefits of All-Wheel Drive and winter tires so that everyone can make the best decision for themselves.
When is All Wheel Drive (AWD) Most Useful?
Under normal driving conditions, most drivers do not need a car with All Wheel Drive. All Wheel Drive only becomes useful when you have limited traction, such as in snowy, icy, or wet conditions. In most conditions, a car with Front Wheel Drive, or even Rear Wheel Drive, will handle the conditions just fine. Many Subaru drivers go places where AWD is useful, like getting out of a snowy parking space while skiing on Mt. Hood or driving down a muddy road to go camping. Or, they just want to feel more comfortable in our typical Pacific Northwest wet winter weather.
All Wheel Drive does not mean you can drive anywhere you want at any speed you want. You are still limited by the traction your tires provide. After all, four tires with zero traction are no better than two tires with no traction.
AWD is Really Only Helpful When Accelerating
The big misconception about AWD is that it helps in all driving conditions. But, when turning or braking AWD is rarely helpful. AWD really only helps when starting from a stop in slippery conditions and you lose traction on one or two wheels. AWD can shift power to the wheels that have traction to help you get going.
The downside to AWD is that it can make drivers overconfident in their cars’ traction. This can lead to driving too fast in slippery conditions and losing control in a turn, or not being able to stop for traffic ahead.
There are advantages to having dedicated winter tires on all four wheels. Most importantly, when you are trying to stop in slippery conditions, or even just turn a corner, having more traction will help you from sliding into the car in front of you, or into oncoming traffic.
For an easy visual example of the difference between all-season tires and winter tires, here are two videos.
The first video shows the advantage winter tires have over all-season tires while accelerating, braking, and turning.
The following video shows how a small SUV with winter tires outperforms the same SUV with All Wheel Drive and all-season tires while accelerating up a slippery hill.
How are Winter Tires Different Than All Season Tires?
Most people never think about their tires, because until they get a flat, or wear out, modern tires work really well. All-season tires are still a compromise. They don’t handle as sharply as a dedicated summer tire and won’t perform as well on snow or ice as a dedicated winter tire.
Winter tires have three primary features that help them perform better.
First, the rubber compound is designed to stay soft in cold weather, which gives the tires better grip on snow and ice.
Second, they have small sipes (they look like little zig-zags) that are designed to grip icy surfaces. Some tire shops offer a “siping” service that cuts small grooves into your tires, but these don’t work as well as the ones that are molded directly into the tires.
Finally, winter tires have tread pattern that helps grip snow at slow speeds, but also flings off the snow at higher speeds. Gripping the snow at slow speeds allows the snow to grip to itself, much like building a snowball.
The downside to these features is that the soft rubber compound wears quickly in hot weather, and all the sipes and special tread pattern make the tires feel squishy in curves or at higher speeds.
Should I Buy a Used Set of Winter Tires?
We recommend new snow tires versus buying a used set. If you have them mounted on a dedicated set of rims then changing over from summer to winter is a relatively easy process. You could do it yourself in your driveway with a sturdy jack and lug wrench. Most tires stores are also happy to install your winter tires for you for about $10 per wheel.
We don’t recommend installing snow tires on the same rims as your summer or all-season tires. If you continually mount and dismount different tires on the same rims you risk damaging the tires or the rims. Plus it typically costs $80 or more to have a set of tires mounted and balanced. And of course you’ll need to do that twice a year to switch back and forth.
If you do want to buy a set of used snow tires, they are out there. In the Pacific Northwest you will often find used sets for sale from people that sold their Subaru and still had the snow tires in the garage. However if you go this route you need to pay attention to more than just the tread depth.
One of the main benefits of winter tires are the softer rubber compounds, and unfortunately tires get harder and less flexible as they age. Check the side of the tire for the date code, and stay away from any winter tires manufactured more than 5 years ago. There are also some tire brands that have a winter compound when new, than turns into an all season compound when they wear down to about 4/32”. Bridgestone Blizzaks are one tire like this. Don’t buy a used set of Blizzaks with 4/32’ tread and expect them to perform like new. Whenever possible we recommend buying winter tires new.
Do I Need Studs or Studded Winter Tires?
No. With modern tire design and rubber compounds studs only help in very limited cases such as on pure ice. But even then their advantage is very small. The rest of the time they actually perform worse than studless winter tires. Plus they are loud, and at higher speeds the studs can be ejected from the tires. But most importantly, the studs wear those annoying grooves in the highways that then fill with water, making driving the rest of the year more dangerous for everyone else. We at Esprit Motors do not recommend studded winter tires.
Can I Just Use Chains On My Subaru?
According to Subaru, it is not recommended to use chains on most of their models, due to a lack of clearance for the chains between the tires and vehicle body. So, your best option for serious winter driving is a dedicated set of snow tires. If you are planning on using chains on your Subaru check that they fit before heading to the mountain and getting stuck.