Like most people, I fancy myself a bit above-average when it comes to driving skill. Whether that pat on my own back is deserved or not, after a lifetime of Michigan weather I’ve shed most qualms about adverse road conditions. Black ice, slippery sleet, drifting snow — bring it on, and my masterful command of the wheel will prevail.

But it recently came to my attention that skill, determination and experience do not trump lack of traction. Inching the hatchback forth and back, helplessly, on packed snow, as other motorists looked on in annoyance, was not the best way to kick off a festive holiday evening.

As the rubber whirred futilely against the clumps of ice and the car started to slew downslope toward a drainage ditch, I mentally kicked myself for procrastinating on tire replacement.

Shopping for a new set of treads the next day, it dawned on me that I’ve never owned snow tires — or winter tires, as they are known in the industry. I’m not sure anyone else I know has, either. To understand the pros and cons of outfitting a passenger vehicle with winter tires, I tapped Richard Sherman, an automotive engineer specializing in tire design and failure analysis.

“Snow tires are designed to take advantage of the compressive properties of snow,” said Sherman, who is based in Lancaster, Penn. Formerly a designer with a major tire manufacturer, he now works as an independent consultant and vehicle crash causation expert. “They give you a better bite.”

In a nutshell, all-season street-tire ribs typically are straight, and designed to wick water off the road surface. Snow tire treads are shaped and angled differently, to dig into and then expel the snow.

Also, the rubber compounds on winter tires are designed to stay softer in cold temperatures, where regular tires might stiffen and lose flexibility.

Sherman cautions winter tire owners not to get too cocky.

“Snow tires get you going — they are not an excuse to go faster in adverse conditions,” he said.

Can you drive winter tires year-round? If you do, expect a noisy ride and rapid wear to the tires, Sherman said. To economize, he suggested, shop for used steel wheels and moderately priced snow tires; a $500 investment should buy you several years of wear.

Other considerations when contemplating winter tires are storing them properly in a dry location out of sunlight, and of course devoting time to getting the swap done, around Thanksgiving and Easter.

If you’re not up for maintaining a second set of tires, make sure your all-season tires are up to the demands of ice and snow.

In the United States, federal law regulates tire standards and testing, and most new ones come with about 10-32nds of an inch of tread. Conventional wisdom says that if you insert a penny upside down and facing you, and can see all of Abraham Lincoln’s head, your remaining tread is less than 2-32nds and the tires should be replaced.

In most states, 2-32nds is also the legal minimum tread depth, and many tires are warranted to that level of wear.

“I wouldn’t suggest driving all-season tires in snow with less than 4-32nds of tread remaining,” said Sherman. You can use a quarter coin to check the tread wear; there are 4-32nds of an inch from the edge of the coin to the top of George Washington’s head.

Another way to check wear is to look for indicator bars embedded in the tread across the tire; they start to show up when the rubber around them wears down. Some manufacturers put a little icon, like a Michelin Man or Goodyear logo, on the edge of the tire to help you find the bars.

When you hit the stores or the computer to shop for tires, understand basics such as the Uniform Tire Quality Grading standards, set by the National Highway Traffic Safety Administration. These A-B-C ratings provide information about a tire’s performance in NHTSA tests of tread wear, traction and temperature. A complete primer on the standards and many other tire-related safety and shopping tips is at

Melissa Preddy is a Michigan based freelance writer. Reach her via

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