This advice is based on the theory that a narrower tire exerts more pressure on a smaller contact patch, thus providing better grip. Against this is the idea speaking in favor of wider shoes, which assumes that a wider tire generally offers better grip due to an overall larger area in contact with the surface.
But as Jonathan Benson of Tire Reviews found out during testing, tire width doesn’t matter all that much when driving in snow. He demonstrates this in a video in which he tried different sized sets of Hankook tires that he tested on a rear-wheel drive BMW 320i while driving on a snowy circuit.
Jonathan shod the car in four combinations – the narrowest tires were 205/60 R16, followed by 225/45 R18 and 255/35 R19 tires. And there was also a combination of 255/35 R19 front and 275/35 R19 rear tires.
Benson tested the properties of Hankook’s winter tires in several disciplines, testing their impact on handling, traction and braking.
He focused on controllability while driving on a snowy circuit, on which he also measured his time. The fastest BMW reached the finish line on 225/45 R18 tires, the slowest was on the largest ones. Although Jonathan felt certain subjective differences between the individual shoes from behind the wheel, they were, according to him, incredibly small. And there were no big differences between the times achieved either.
Next, Benson focused on traction on snow, which he examined when accelerating from rest to 35 km/h. The BMW accelerated best on the narrowest tires (in 6.35 seconds), worst on wider ones (in 6.8 seconds).
However, the narrowest tires subsequently performed the worst when braking on snow. The 225/45 R18 tires dominated this test – again with relatively small differences.
And then it was ice time. Again, the smallest tires had the best traction on it, and the 225/45 R18 tires had the worst. During deceleration, the combination of the widest available tires worked best, the narrowest tires did the worst braking. But even in these tests, the differences were not significant.
Benson thus offers interesting conclusions. On snow in his test, the narrowest tires performed best and the widest the worst, but on ice the smallest tires were followed by the widest combination.
Overall, the narrowest shoe won the test, but Jonathan points out that the fact that the winning winter tires represent a different Hankook model than the other three sizes could have played a role in this result. And they have a different design. Unfortunately, the exact same type in all tested dimensions was not available.
But this fact simultaneously underlines Benson’s main conclusion of the test. According to him, the quality of winter tires plays a much bigger role than their size. The test results underline this by the fact that there were objectively minimal differences between the different dimensions of the same model of winter tires on snow and ice.
So Jonathan recommends that you focus mainly on reputable brands and tires with positive and recommendable reviews when choosing. This is said to be more important than stressing about choosing a size.