Getting a grip on the nitty-gritty of winter tires.

CAA Auto Advice November 20, 2019
Car driving on snow covered remote road.

Most drivers know when the mercury regularly dips below 7 degrees Celsius, it is time for your car to wear its winter tires. The rubber compounds from which a winter tire are made contain elements which allow them to remain pliable in cold temperatures. Stiff rubber simply doesn’t offer as much grip; put on a pair of flip flops during the next ice storm to discover what we’re talking about.

Still, winter tires aren’t a lot of help if they’re too smooth. Making sure your tires have the proper and safe level of tread depth is easy. 

How to check your treads.

Reach into your pocket and grab the toonie that’s left over from the change you received at Tim Horton’s this morning. With the coin positioned upright, place it between the tire’s tread block. If the tread only reaches so far as the ‘Canada’ or ‘Dollars’ letters, your tires are extremely worn and should be replaced. 

Tires also have built in indicators called wear bars. They are small ribs of non-structural rubber that span the gap between those meaty tread blocks. They’re hard to see when there is a lot of tread but become prominently visible when the tire becomes worn to the point of needing replacement. Some brands, Nokian in particular, mold the numbers 80/60/40 into the rubber. They represent the rough amount of remaining life and slowly become visible as the tread wears away. Many winter tires start life with about 12/32” of tread depth and most experts advocate for their replacement when that number is down to roughly 6/32”. This is much different from all season tires whose legal replacement limit is 2/32”.
Winter tire of car driving in show.

Winter tires refresher course.

A quick lesson, in case you fell asleep in class: mechanical attributes (the tread pattern) and molecular construction (the rubber compound) are the two features which separate a winter tire from an all-season hoop. 

The first is easy to visually see. It’ll not escape your notice that tread blocks on a winter tire are packed with little zig-zag cut features. These are called sipes. They open up slightly when pressed into the road surface, creating extra biting surfaces to provide more grip. The Continental VikingContact 7, new for this year, is a good example. A close examination of those tread blocks will also reveal edges shaped like a serrated blade, another design decision intended to create extra grip, not unlike when a cat’s claws dig into the sofa. This can be seen on the Yokohama iceGUARD iG53 tire.

Visually seeing the rubber compound in a winter tire isn’t possible, nor is finding out specifically what the compounds are comprised of. Tire companies play their cards close to their chest, guarding its recipes closer than Colonel Sanders guarded the 11 herbs and spices. Still, if one were to press on a winter tire in the way one would test the freshness of a melon at the supermarket, they’d find it to be much more pliable than a high-performance summer tire.

Still have a few questions? CAA Members can always contact our band of Auto Experts for advice. 

Drive safely, everyone!

 

CAA Auto Advice.

Do you have your own car-related questions? We'd like to help.

CAA’s Auto Advice team provides Members with free automotive advice. If you have questions about car care, buying a new or used vehicle, auto repairs, vehicle inspection, driving costs and more, contact our Auto Advisors by phone at: 1-866-464-6448 or email autoadvice@caasco.ca. Our licensed technicians and experts will be able to assist you on many of your of car related questions.


Written by: Matthew Guy.