Every so often, motorists are faced with the question, “Are these tires worn out? Should I replace them or can they go further?” The fact that you are asking the question means that your tires are approaching the end of their lifespan. But what is a usable tread depth and what are the ramifications of pushing tires with a shallow tread? We recently ran across a video at the Tirerack.com that explains what is acceptable in terms of tread depth. They perform some wet-weather emergency stop testing with tread depths of 2/32″ (1.6mm), 4/32″ (3.18mm) and 10/32″ (7.9mm). They also perform the same testing with a pickup truck. The stopping distances with each of these respective tread depths is eye-opening to say the least. The minimum legal tire tread depth in Canada is 2mm. For winter traction, the rule of thumb is 6mm minimum. New tires have between 11mm and 13mm.
It has always been our view that good tires are the best life insurance you can own. Never scrimp on quality because with tires you get what you pay for. Do regular tire rotations and have an annual wheel alignment performed. Most importantly check your tire’s air pressure. Keep a pressure gauge in your glove box and check it every couple of weeks (and especially before a long trip). This bit of maintenance will improve your tire lifespan and optimize handling and fuel economy.
We should also note that we are huge advocates of winter ice radials. If you have never tried a set, save up for next winter and you will be wondering how you ever lived without them. By the way, we have no relationship with Tirerack.com, but we do find their site to be a very useful source for researching different brands of tires. The consumer generated survey scores and reviews are especially valuable.