Why a quarter is an important tool when checking your tires – The ClassicCars.com Journal | CarTailz

Editor’s Note: This article was originally published on October 30, 2020.

Believe it or not, from time to time you actually have to watch out for those big donut-shaped black rubber objects that are the only connection between your vehicle and the places you drive it.

It doesn’t matter if your vehicle is a multi-million dollar supercar, a valuable – or at least cherished – classic, a goods hauling truck (or an RV, boat, or horse trailer), or a service provider, or a mundane minivan used for work, in the park and went shopping. Ultimately, your acceleration, steering and braking – and your safety and that of others in your vehicle – are affected by your tires and their contact with the dry or wet pavement, gravel, dirt, sand, snow and/or ice you drive on. reached .

And here’s the truly frightening fact: Your safety is also – quite literally – compromised by the tires that support all vehicles around you on that pavement, gravel, dirt, sand, snow and/or ice.

OK, so you can’t go around checking everyone else’s tires, but you can be responsible for the punctures on the cars in your driveway and garage and, yes, your car collection if you’re one of those people whose hobby is driving, rather than just to polish and admiring.

So how do we check our tires? Do those numbers on the side panel really matter? Does this Lincoln penny thing really work? What if I have a lot of tread but the tires are older, when should I replace them?

We start with the famous Lincoln penny test. Traditionally, the quickest and easiest way to check the tread wear on your tires was to take an ordinary penny, turn President Lincoln upside down, and stick the coin in the tread of each of your tires. When your tires were so worn you could still see the top of Honest Abe’s head, it was time to replace them.

But no more, says Matt Edmonds, Executive Vice President of TireRack.com. Edmonds explains that if you can see Lincoln’s head, your tires have less than 2/32 of an inch of remaining tread and you’re already at risk of greatly increased stopping distances, especially if you live in a place where it rains frequently.

A much better benchmark, Edmonds said, is to use a quarter of George Washington.

“Inflation has taken us from a penny to a quarter,” he jokes.

Use the Washington Quarter to recheck the tread depth on all four tires. If you can see the top of Washington’s head, you’re down to 4/32 of an inch in profile. Is this number significant? Yes, and especially if you live where it snows. Edmonds warns that even if you have all-season tires on your car, if you live in the snow belt you need at least 6/32 tread to drive safely into winter weather.

Another thing to consider is the age of your tires. The rule of thumb, Edmonds said, is that a tire has a six-year lifespan and a 10-year lifespan. Sounds confusing, but it isn’t.

You see, tires have a birthday, a date of birth, and it’s molded into the sidewall. There’s a good chance a tire will be stored in a warehouse for a year or two before you buy it, and that’s fine, Edmonds said, provided the tire hasn’t been sitting behind a store but has been stored at a temperature-controlled Attachment.

Basically, the six-year clock starts ticking when the tire is mounted on a vehicle. Where the 10 year lifespan might make sense is if someone is buying a used car or a collector car with low mileage but aging tires.

For example, someone buys a 7 or 8 year old Porsche with low mileage and original tires. The new owner sees a good profile left and decides to do a track day before buying a new set. The result of such a strain on old tires is rarely a pleasant experience, he adds.

The age of the tires can be particularly critical for so-called special vehicles, e.g. B. the Dodge Viper, which has different tires front and rear. Such tires may only be manufactured periodically and may be older than they appear.

So how do you find out the date of birth of your tires? Look at the sidewall, find the DOT numbers and the last four indicate the week and year the tire was made. (I just checked the tires on my pickup truck. The last four numbers are 2219, 2219, 2319 and 2719, so they were produced in the 22nd, 23rd and 27th week of 2019.)

The most neglected aspect of tire care checks the correct air pressure.

“If a tire is properly inflated, it can function properly,” Edmonds said, citing motorsport as an example: “What do you do when you want to adjust the car’s handling? They adjust the air pressure.”

Such adjustments on the race track are made by experienced experts. On the road, however, a tire with a loss of pressure of even 10 percent — say from 35 pounds to 32.5 pounds — can become damaged, and you can’t see its damage until you remove the tire from the wheel and the remaining ” Crum Rubber” bits see as the tire deteriorates.

New cars have tire pressure monitoring systems that alert the driver when the pressure is too low. But these systems work on batteries that can fail, and in some older systems that don’t have direct sensors but rather the work of the anti-lock sensors, all four tires could have 15 pounds less and the system would be fooled into thinking everything would be fine.

In addition, there is nothing wrong with the good old hand tire gauge, with which you can not only check the air pressure (in cold tires that have not been heated up by driving) and check tire wear below.

There is a lot of other information written on the sidewalls of your tires, whether they are all-season, all-terrain, summer or winter tires. Also, a rating of the tread as to whether they are likely to wear out sooner or later, a traction rating based on the ability to stop on wet roads, a temperature class based on the tire’s heat resistance, and a load index based on the particular weight tires can safely carry.

Also given is a maximum speed rating ranging from L – 75 mph for some off-road and light truck tires – through various letters up to V – 149 mph.

Typical American family vehicles typically run on tires rated S (112 mph) or T (118 mph).

However, there are also very powerful Z tires, which are now divided into W – up to 168 mph – and Y – up to 186 mph – groupings. For high-speed exotic vehicles, there is also a (Y) rating for tires capable of speeds in excess of 186 mph.

Another note from Edmonds, and this one for electric vehicle owners:

“EVs are tough on tires,” he said, explaining that the instantaneous availability of maximum torque and the added power of regenerative braking means EV tires wear out faster than internal combustion engine cars.

So have the tire gauge and a Washington quarter ready.

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