The merits of using winter tires during the cold months of the year have been widely discussed, particularly after Quebec made it mandatory to run season-appropriate rubber between December 15 and March 15 a few years back.
But you don’t read too many articles stressing the importance of making the switch back come spring. You might be surprised to find out many Canadians keep rubber designed for snow and ice on their vehicles even when people are milling about in shorts and tees. [For example, my parents! —Ed.]
At a Michelin safe summer driving event earlier this month, driving instructor and racer Carl Nadeau explained why it is equally important to switch back to the all-season or summer tires in warmer weather.
Trial by fire
“I always compare tires to footwear. Like, you get boots in the winter, and then you get running shoes and then sandals,” says Nadeau. “Of course the running shoe can be a real good all-around shoe, and it’s the same for tires. A winter tire is great in the winter—the rubber compound stays soft, but that softness of rubber doesn’t cope with summer.”
Winter tires’ ability to stay soft and flexible at low temperatures is great for digging into snow and gaining traction, but that translates into a wobbly tire that actually takes longer to grip into pavement and come to a complete stop in summer weather.
To demonstrate, I took two Toyota Camrys — one fitted with Michelin’s Primacy summers and another with X-Ice winters (neither pictured below) — spiritedly around a tight parking lot slalom on a warm spring afternoon, and the difference was surprising.
Whereas I was sliding around the corners with the X-Ice, the Primacys allowed me to turn sharply and confidently (as much as a Camry can, anyway). Under hard braking at the end, the summers stopped within a significantly shorter distance.
Not all rubber is equal
“A lot of people think ‘Well, it’s a round black rubber section that just touches the road,’” says Nadeau. “The reality is it’s not meant for that. The [winter] tire literally disintegrates [on warm pavement], and on top of that, the sidewall of the winter tire is not as strong as the all-season or summer tire.”
“So what we’ve seen with the [summer tire] is that during your initial driving input, when you’re doing to start the corner, the tire reacts right away. The winter tire is more lazy—when you turn you feel like the sidewall is moving, you feel the tread itself moving under the car and then the car finally starts changing direction.”
Even if it’s just one second’s worth of vehicle reaction time the driver loses, it could make all the difference in an emergency situation.
But what about summer versus all-season tires?
Summer vs all-season tires
Designed for handling and stability, summer tires are made from a compound that is soft and grippy for maximum grip. The tradeoff is that same compound, while increasing performance, may wear out quicker than an all-season tire’s.
The tire can be noisier as well when rolling, and a stiff sidewall can translate into a bumpier ride. Wider tread provides more contact with the road surface and gives better traction in dry conditions and damp conditions. When the temperature dips, however, the rubber hardens and the tire loses its grip.
Even if it’s one second of vehicle reaction time the driver loses, it could make all the difference
On the other hand you’ve the “all-season,” a name which can be a bit misleading. It’s not really a tire fit for every weather condition—in reality it is a compromise. It’s great for rainy climates because, generally speaking, the grooves in the tread pattern siphon water away well when going over puddles to remain in contact with the pavement rather than gliding over the water (hydroplaning). All-seasons are designed with comfort and longevity in mind, and can even function in light snow conditions, although they’re not ideal for that.
“The message we want to send to people is if you have winter tires on your car for summer, please just change them to all-seasons or summers,” says Nadeau.