Troubleshooter: Why tire tread only tells one side of the story

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If this isn’t a given, it should be; all licensed drivers should know how to easily recognize worn tires and when they should be replaced. Simple right? If no one took the time to teach you how to do an effective walk-around inspection of your vehicle (which should always include inspecting the tires), or if you simply can’t be bothered, you have absolutely no business on public roads. Tires are one of the most important safety and functional features of our autos, and only concentrating on tread wear may lead to disastrous results.

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Troubleshooter: Why tire tread only tells one side of the story Back to video

If you need a refresher on tread wear, it needs to be measured with a small, inexpensive special tool called a tread-depth gauge. The tip of the gauge is placed on raised rubber bars at the bottom of the tread grooves known as wear or indicator bars. They run across the face of the tire at a least 4 spots around it and when the remaining tread gets down to 4/32” or lower, (for summer/all-season tires), they’re pretty much done. As most winter tires start their life with much deeper tread, and seeing that they depend on that depth for winter traction, their expiry wear can be higher, such as 6/32” or 7/32”.

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But treads (or lack thereof) aren’t the only reasons to start rubber shopping. Weather checking or dry-cracking is something that can reduce the structural strength of tires and lead to blow-outs. Contrary to popular opinion, there are no expiry dates on tires. If they’re properly stored and shielded from UV radiation, as well as extreme low humidity, they can literally last for years. But those two conditions of our outdoor environment can lead to small cracks developing on the tread face and sidewall of the tire. Most jurisdictions won’t condemn a tire for weather cracks unless they’re deep enough to expose the light-coloured support cords underneath. Using a dull blade or flat screwdriver is the easiest way to see if this is the case. But consider that most provincial and territorial vehicle safety standards are bare-minimum, so you may not want to wait that long.

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Sidewall bulges are another sign of trouble. Few drivers would look at a noticeable outward bump on a tire sidewall and think it was OK and safe to drive on, but even slight deformations may indicate a problem underneath. Contrary to popular belief, most of these bumps aren’t defects in the tire, but rather the results of curb impacts. And they shouldn’t be confused with the normal small and slight indentations in the sidewall that are completely normal. For most tires you will find 5 or 6 of these little dips evenly spaced around the tire.

If you follow professional drivers’ habits, you should be doing a walk-around check before every trip out. While that’s probably a stretch for the average commuter, completing a check-over once or twice a week isn’t overkill. And as tire problems can quickly turn into road nightmares without much warning, keeping on top of things pays off with improved safety and dependability.