Treading the line: It’s time to rethink keeping those winter tires on all summer long
Intuitively, most drivers know that winter tires — commonly referred to as snow tires — are less effective on summer roads than a summer or good high quality all-season tire.
That assumption was — forgive the pun — driven home last week by professional Canadian race-car driver and drift instructor Carl Nadeau. If there’s anyone who should understand tire characteristics, it’s Carl — and believe me, he does.
The Michelin Test
Quite bravely, Michelin convened a driving event here in Vancouver at the PNE grounds recently in which they allowed participants to push identical cars shod in a variety of tires on a closed course under the instruction of master driver Nadeau. The point of the session was to demonstrate the potential loss of traction when winter tires are used on summer roads, and also to highlight the effectiveness of Michelin’s Premier all-season tire, which re-establishes an inner tread-pattern with long-term wear. Michelin refers to this unique technology as Evergrip.
Most interesting to me was the dramatic difference between winter and non-winter tires on both wet and dry surfaces in moderate temperatures. For this demonstration, two identical Toyota Camrys were prepared by Michelin.
The only difference was whether they rolled on Michelin X-Ice winter tires or Michelin Primacy all-season tires.
Twisty with diminishing-radius turns, the course designed by Nadeau was a challenging one thankfully composed of harmless cones given my over-exuberance at times. Nadeau made it clear, we were to push the cars — actually their tires — to the limit with the goal of feeling and hearing every nuance of sound and vibration to understand what was happening where “rubber meets the road.”
Unlike the humans relying upon them, tires are actually good communicators once their articulation is recognized and understood. This enables a trained driver to sense the edge of grip before the line is crossed. Where that line resides differs dramatically depending on a number of tire-related factors, not the least of which are tire type (i.e. winter vs. summer), tire wear, and tire inflation.
All tires used in the Michelin event were new and properly inflated. First up in my series of test runs were Michelin’s Primacy all-season tires. The track had just been doused by the on-site rain truck, yet I heeded Nadeau’s instructions and went for it with three laps that had the Camry writhing in agony as the Primacys clawed for what little grip could be pulled from the slick pavement. “Take note of your speed around the track,” Nadeau firmly announced as I fought to keep the Camry between the cones through the corkscrew and stop boxes.
The vehicle’s stability control program had been deactivated to ensure that no digitally processed intervention would aid me in my struggle to manage understeer followed by oversteer. Each lap faster than the last, I was at the top of my game — or so I thought.
That game went radically south when I hit the track in the Camry shod in Michelin’s X-Ice winter tire. Now, in the world of winter tires, the X-Ice is a top contender. As such, one may think that it would perform as good as a non-winter tire on wet pavement. It has huge water-channelling capability and a soft, grippy rubber compound — right? Well that may be the case, but it doesn’t translate into a tire with anywhere near the performance capacity of a good summer or all-season tire.
I was a wild-man out of control on the track with the X-Ice tires, taking out cones like a weed-whacker in a patch of dandelions.
Not to sound too dramatic about it, but I was astonished at the decline in grip and control that I experienced with the winter tires. There was no possible way of reaching the same speed with these tires that I had attained beforehand. And when it came to a full emergency stop, the Camry slid well past the stop-point of the Primacy tires, and frankly past my expected point of rest.
Still want to run winters in the summer?
To be honest, I went into Michelin’s hands-on tire demonstration feeling a little ho-hum about the adventure. I came away from the event with a whole new perspective on tire characteristics, and the importance of matching tires to seasons and driving needs. They don’t teach this stuff in driving schools, and they should.
Many drivers, not just those new to the wheel, fail to understand the performance characteristics of their tires, and worse yet, fail to recognize the language they speak. While it may not be practical for all who drive to undergo a Carl Nadeau wake-up call, with the approach of summer, motorists can easily enhance safety by ensuring that their tires are correct for the season, have adequate tread depth, and are properly inflated. They can also expect to save fuel by switching to all-season or summer tires whence winter retreats.