Winter tires, how the rubber meets the road

When the topic of winter tires was raised during a recent team meeting with my colleagues at the Traffic Injury Research Foundation (TIRF), I realized I had little understanding of the importance of winter tires to the safety of drivers during winter months. This is despite the benefit of decades of experience as a driver and having been raised in Northern Minnesota, USA, and returning to the state to live for the last decade. The conversation touched on the ideal outside temperature when winter tires, why installing just two tires can be dangerous, and whether they’re really necessary in northern states. Yes, yes they are.

I was also surprised to learn that snow tires are distinct from winter tires because you don’t even wait until the snow flies to install winter tires either. Winter tires are more effective than summer or even all-season tires starting at 45°F or +7°C which in some places can start in late September. So, here’s the Cliff notes story on winter tires.

Initially, I had just assumed that my Canadian colleagues were calling snow tires winter tires (you know how those Canadians seem to have some different words than us Americans…. like runners instead of sneakers). But I was mistaken. So, I decided I wanted to:

• determine why I was clueless about using winter tires because I was pretty sure I wasn’t alone;
• consider why there are so many people in the northern United States that do not use winter tires; and,
• learn how winter tires are different from the ubiquitous all-season tires.

This blog shares the information I discovered, research that supports the benefits of winter tires including traction and handling, as well as recommendations for safe installation.

Fun fact: TIRF’s 2012 Winter Tires: A Review of Research on Effectiveness and Use report has been downloaded over 7,000 times with 27 media articles referencing it in just the last five years alone. It’s clearly a topic of interest every Fall, so let’s explore why.

Snow vs winter vs all-season tires

At this point, I believe it is important to briefly distinguish between snow and winter tires; a distinction that was new to me. Erroneously, snow tires have been referred to as winter tires and vice versa. However, the differences between the two types of tires are significant.  Generally, snow tires were created with deep tread patterns to optimize driving in deep snow. Conversely, winter tires include a broad category of tires that were designed for all winter road conditions including wet, slush-covered, snow-covered, ice-covered, or dry cold surfaces.

Every October, in the 1950s and 60s, my father would put snow tires on our family car. The later version of snow tires may also have included metal studs which provided extra gripping on iced-over roadways. In 1966, the studded tire option was outlawed in most areas of Minnesota due to the damage the studs caused to the surface of roadways and hazardous inhalable dust particles. I don’t know at what point my father stopped putting snow tires on the car, but I think it was sometime in the mid- to late-1970s when all-season tires were introduced more widely.

In the creation of this blog, my unscientific poll of a few dozen acquaintances revealed that none of them have used snow or winter tires from the mid-1980s to present day unless they lived in isolated rural and/or mountainous regions of the country. Also, none of them could recall ever being informed of or receiving a pitch for the importance of winter tires. To this day, I have not seen any public service announcements or advertisements related to winter tires. Further, during the ‘80’s, all-season tires were hitting the market, widely advertised, and were considered by many as a more economical and effective alternative to having two sets of tires. So, perhaps, our collective ignorance can be forgiven.

How & why all-season tires entered the picture

The gain in the popularity of all-season tires in the U.S. seems to be influenced by a few different factors.

• Improvements in tire technology created and introduced tires that provided versatility with good performance in both warm and cold temperatures and dry and wet conditions, including light snow.
• Vehicle owners desired convenience and cost-effectiveness during the difficult economic time of the late 1970s into the next decade. Thus, vehicle owners opted for one set of tires that were made to handle a range of conditions, had good tread life, and eliminated their perceived need to make seasonal tire changes which in turn decreased maintenance costs.
• The automobile industry began issuing manufactured vehicles with all-season tires as standard equipment and recommended all-season tires for myriad types of vehicles.

How all-season tires stack up against winter tires

So, if all-season tires provide the aforementioned benefits, why bother with winter tires if you live in an area that often has harsh winter conditions? Let’s compare the differences between all-season tires and winter tires.

• Differing rubber compounds.
  • All-season tires consist of rubber compounds that balance between warm and cold temperatures but won’t function optimally in winter conditions. Many contain silica additives in the rubber to improve wet traction and durability.
  • Winter tires consist of special rubber compounds to remain flexible for improved grip on ice and snow and provide better traction in freezing weather, typically below 45°F or +7°C.

• Design of tread patterns.
  • All-season tires have a tread pattern that is shallower, less pronounced, and channels water away from the tire to prevent hydroplaning and, thus, allows for effective handling on wet, dry, and lightly snow-covered roadways.
  • Winter tires have deep treads with more pronounced patterns and large, irregularly shaped tread blocks as well as more flexible rubber compounds giving them increased traction on snow and ice. Additionally, these tires have small grooves that provide biting edges to improve their grip and larger grooves to help channel snow, slush, and water away from the tire, reducing the risk of hydroplaning.

• Traction and handling.
  • All-season tires have poorer traction performance in temperatures below 45°F/+7°C, deep snow, and on icy roadways.
  • Winter tires have much better traction, handling, and braking performance in snow and icy conditions and are specifically designed for winter driving and cold weather.

• Overall performance.
  • All-season tires have a good balance that allows for both summer and winter driving in moderate-weather locations where it is rare to experience extreme weather. Most carry the M+S rating meaning they meet performance requirements in mud and snow. Some with the 3PMSF symbol (especially those marketed as all-weather tires) meet standards for severe snow service.
  • Winter tires are safer in wintery conditions with enhanced traction, handling, and braking performance in a variety of cold weather conditions. However, the tread will wear faster and have less grip in warm weather. So, switching back to summer tires when temperatures are consistently over 45°F/+7°C is prudent as well.

• Cost and durability. To ascertain the typical costs for tires I did an internet search for tire prices. Keep in mind these price ranges are for standard tires on standard vehicles. If your vehicle has low-profile tires or larger tires, the cost will vary. The cost for both types of tires is dependent on the vehicle and its required tire size. Additionally, one should consider the cost of installation and balancing.
  • All-season tires are usually cheaper with a longer tread life if used in moderate climates. My internet shopping indicated economy tires cost between $50 to $100 US per tire, mid-range tires between $100 to $200 per tire, and high-performance or specialty tires between $200 to $400 per tire.
  • Winter tires are often more expensive, and their life span is greatly reduced if used year-round. My internet shopping indicated the cost of economy winter tires to be between $60 and $120 per tire, mid-range tires between $120 to $200 per tire, and high-performance or specialty winter tires will cost between $200 to $400 per tire.

Four vs two winter tires

Finally, I was curious about whether one needs to have four winter tires or if just two would suffice. Given what I had already learned, I anticipated that I would find that four winter tires were better than two due to better handling and performance. The reasons for this are:

• If only two tires are used (presumedly on the back or front of the vehicle) the traction will be unbalanced, making it harder to control when cornering or taking emergency maneuvers. Four winter tires greatly improve the vehicle’s ability to corner.
• To maintain stability, having four tires with the same level of grip is important. There is a potential loss of control or skidding with mismatched tires. This is essential for all-wheel-drive and four-wheel-drive vehicles.
• Braking distances are shorter with four winter tires than with two.
• If only two winter tires are installed, a vehicle may experience oversteering with the rear of the vehicle sliding out or understeering when the front of the vehicle doesn’t steer as expected.

Trailer tires

And, just to ensure we’ve covered all the bases, I wanted to include a brief word about trailer tires. While the trailering season is coming to an end for many adventurers. Some have off-road or all-season trailers for exploring the great outdoors all year round. It’s also important to ensure your trailer tires are not only in good condition but are the right tires for the conditions. This also applies to utility trailers used for a range of tasks from hauling yard waste to home improvement projects or transporting larger items like snowmobiles.

Summer driving with a trailer typically involves longer trips which makes well-maintained tires crucial to avoid overheating and tread separation. However, winter driving with a trailer can involve ice and snow, making tire grip essential. Tires with adequate tread depth and the right rubber compound will perform better.

Regular tire checks for pressure, tread depth, and overall condition are key for safety throughout the year, ensuring the utility trailer performs well and minimizing the risk of tire failure which can result in a crash.

Wrapping it up

The purpose of writing this blog was to bring attention to and educate drivers (like me) on the road safety advantages of winter tires for those of us who live in climates that regularly experience typical and even extreme winter conditions. I don’t know all the reasons winter tires are not more widely presented or even advertised but I do think they deserve more exposure for all our sakes.

These related topics share more information about winter tires and general tire maintenance:

• The Cold, Hard Facts about Winter Tires and What Everyone Should Know to Stay Safe While Wintering in Canada https://tirf.ca/blog/winter-tires/
• Safe Winter Driving Starts with Winter Tires infographic https://tirf.ca/download/safe-winter-driving-winter-tires/
• You’re ready to explore Canada this summer, but can your tires handle the pressure? https://tirf.ca/blog/can-your-tires-handle-the-pressure/
• Winter Tires: A Review of Research on Effectiveness and Use, https://tirf.ca/TIRFCAD12G

#MySafeRoadHome blog authors: Carl Wicklund, TIRF USA Senior Advisor, previously developed and managed several community-based programs for justice-involved individuals, served as Court Services Director for a three-county community corrections system, was for 20 years the Executive Director of the American Probation and Parole Association, and more recently was Director of the Community Justice Division of Volunteers of America – Minnesota/Wisconsin. He has been an active member of TIRF’s Working Group on DWI System Improvements since its inception in 2004.

Source documents and resources:

Brown, S.W., Vanlaar, W.G.M., Robertson, R.D. (2012). Winter Tires: A Review of Research on Effectiveness and Use. Ottawa, Ontario: Traffic Injury Research Foundation. https://tirf.ca/TIRFCAD12G

Gustafsson, M.; Blomqvist, G.; Gudmundsson, A.; Dahl, A.; Swietlicki, E.; Bohgard, M.; Lindbom, J.; and Ljungman, A. 2008. Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material. Science of the Total Environment 393: 226-240. https://doi.org/10.1016/j.scitotenv.2007.12.030

Rubber Association of Canada. 2007a. Tire basics: What drivers should know about tires. The Autosmart Fact Sheet Series. Mississauga, ON.: Rubber Association of Canada. https://tracanada.ca/wp-content/uploads/2021/04/Tire-Basics-What-Drivers-Should-Know-about-Tires.pdf

Russell, R. 2011. Almost time to roll on winter tires. Globe and Mail: October 11. https://www.theglobeandmail.com/globe-drive/culture/commuting/almost-time-to-roll-on-winter-tires/article556935/

Woodrooffe, John (2016). Ten Surprising Findings About Winter Tires: It Is Not Just About Snow, University of Michigan https://public.websites.umich.edu/~umtriswt/PDF/SWT-2016-10.pdf