Despite all the gains in active safety technology that have been applied to cars over the past few years, your car’s tires are still the most critical element in the safety chain. As your car rides on four patches of rubber only about the size of your palm, almost every active safety device must still rely upon the tires as it’s the sole connection of the vehicle to the road.
Modern radial tires are designed to provide consistent service throughout their life. However, it’s important to recognize the signs that your tires are due for replacement, as opposed to waiting until they’re completely worn-out, as that limits the full range of your vehicle’s capabilities.
Out with the Penny, In with the Quarter
It used to be that an easy test to see if you needed to replace your car’s tires was to stick a penny into one of the tread grooves, inserted with Lincoln’s head down. If the tread comes up to Lincoln’s head, the old standard indicated that the tire was worn out and needed to be replaced. There are also government-mandated wear bars in the tire that provide the same information – they are even when the at 2/32” of groove depth. The problem with the test is that people took it to mean that their tires were okay to drive on. That’s not the case. With only 2/32” of tread remaining your tires are beyond the legal limits in all 50 states. You’re actually driving on non-legal tires.
A new test that has been adopted by consumer groups and tire markers alike, and it uses a US Quarter instead. Now you dunk George Washington’s head into the tread and if it reaches just to the top of his head, it’s time to start tire shopping. You have 4/32” of tread which is what most safety groups believe to be the safe limit for tire wear. So next time you’re looking to check the tread depth of your tires, upgrade to a US Quarter.
Be On the Lookout for Irregular Wear
It’s best to measure the tread depth of your tires in various locations across the tread as well as around its circumference. You may find that the measurements come out differently in different locations. For example, if the shoulder area is much lower than the rest of the tire it could be an issue with the vehicle’s alignment, the speed with which one or more drivers take a corner, or even that the tire is or underinflated inflated for a period of time. Another common cause of irregular is worn struts, shocks, or other suspension components. Worn shocks create a strange diagonal wear pattern across the tread that’s unmistakable. Just remember, there’s nothing built into the tire that would cause these types of wear patterns – it’s either use, misuse, or a mechanical condition.
Inspect Your Tires Well
Look for debris the tire may have picked up while driving. Sometimes it’s obvious things like a nail, which if caught in enough time, can be repaired and the tire saved. Wait too long and rust can develop or the hole can get enlarged so that a repair is no longer possible. Look for other debris, especially sharp stones, as they can actually drill their way through the tread of the tire. Removing them is simple but don’t remove anything you suspect may have punctured the tread. Otherwise, you’ll have to jack up the car and find another means to get the now flat tire to the tire dealer as you’ve just let all the air escape.
Another area to inspect is the sidewall. Due to the amount of flexing the sidewall is required to endure while driving, punctures to the sidewall cannot be repaired. Your best solution if you find a puncture or a bulge, typically caused by a pothole or striking a curb, is to get to your tire dealer as soon as possible. However, don’t panic if you want a reverse bulge – that is an area that’s best described as a shallow valley. That’s where splice in the body cords of your tire is located (think about how a belt around your waist is double thickness at the buckle). You’ll typically find it 180 degrees from the valve stem. It’s actually an area of greater strength, due to the overlap of materials, and shouldn’t be of concern.
Tires Have a Life, Too
The National Highway Traffic Safety Administration recommends that tires remain in use no longer than six years. So if you have a six year old car still rolling on its original tires, congratulations, as you’ve obviously taken good care of your tires. To celebrate, drive down to our service center and have all five tire replaced (don’t forget the spare). At six years old the synthetic rubber compounds in the tires start to disintegrate. What happens is that, like your skin, tires ooze a small amount of oil to keep the tread and sidewall area pliable. At a certain point, the tire can no longer provide enough of the needed oil. It’s caused by use, environmental substances like ozone, sunlight, and other factors.
The phenomenon is commonly known as dry rot, and it may appear sooner depending upon where you live and drive. It’s apparent in crumbling of the tread rubber and/or cracks or crazing in the sidewall. Should any of these conditions appear, no matter how long the tires have been on your car, it’s important to have your tires inspected by a tire expert.
So take the time to look at your tires and understand what it is they’re trying to tell you. It will make for safer, more trouble-free driving in the long run.