November may have started with balmy days and temperatures in the upper 70s, but Old Man Winter appears here to stay as the calendar rolled over to December, and a sizable number of drivers in Western Pennsylvania are scheduling appointments to have their regular radials swapped out for snow tires.
“People who get up early in the morning and go out on the road, before salt trucks get out, or are headed to areas where they know they’ll need the extra tread? That’s where snow tires are really helpful,” said Rocco Sarno, vice president at Mar-Mac Tire Co. in New Kensington. “Most people still use all-season tires.”
Snow tires are geared toward winter weather in more ways than one, according to Ian McKenney, senior product manager for Bridgestone’s tire operations in the U.S. and Canada.
“It’s achieved through several design parameters, like unique tread patterns designed to trap snow for excellent traction, an increased number of slots and sipes for biting edges on snow and ice, and additional tread depth to channel away slush and water,” McKenney said.
But it’s not just the treads. The chemical formulation of the rubber that makes up the tire also plays a role.
“There are specialized rubber compounds that remain flexible in cold temperatures, unlike all-season tire compounds that harden as the temperatures drop,” McKenney said. “The proprietary multicell compound in our Blizzak tire lines, for example, stays flexible at cold temperatures while also having small pores integrated into the tread rubber to wick away the thin film of water on the surface of ice.”
The goal of the added flexibility is to maximize the amount of surface area the tire touches.
Gene Millen, an office manager at Highland Tire in Harrison, said drivers who worry about going out in winter weather would do well to have a set of snow tires installed.
“If you feel a little insecure, you’re always going to do better with a snow tire,” Millen said. “The disadvantage is that if you drive a front- or four-wheel-drive vehicle, you have to buy four of them.”
The other disadvantage is that if snow tires are not swapped out once the weather warms, the flexible rubber material will cause them to wear much more quickly.
McKenney said advances in technology have helped to improve the effectiveness of snow tires over the years.
“On the pattern side, we’ve incorporated ‘snow vices’ that run laterally down the grooves of the tires to help trap snow into the tire’s circumferential grooves,” he said. “That’s important because snow-on-snow traction is the best traction you can get in winter conditions, which means we want to trap and hold as much snow into the pattern of the tire as we can.”
While it might seem counterintuitive, McKenney said that as a snow tire rotates, the snow trapped in its treads is contacting and helping to grip the road surface.
McKenney said computer-aided virtual modeling and testing has greatly improved snow tire production.
“We’re able to design our patterns and run them through hundreds of hours of testing before ever building a tire,” he said.
The global winter tire market was estimated at $22.4 billion in 2021, according to Transparency Market Research.
