Your tires might look safe, but are they? Beware as the years go by

Ah, it’s collector car driving season again, and you’ve made all the proper checks and inspections before putting your favorite classic vehicle back on the road.

You go over the checklist: engine in proper tune and filled with fresh oil, transmission gear oil topped up, belts and hoses check out, lights all working, battery’s good and the tires have plenty of tread. 

But wait, what about those tires? They might look like they have lots of life left, but ask yourself this question: How old are they? If they have been on your car for more than 10 years, you could be asking for trouble. 

Old tires are risky. They are prone to all sorts of failures that can cause catastrophic wrecks. They also don’t adhere to the road as well as they used to, which could result in dangerous skids, especially in wet conditions.

You may have put just 10,000 miles on your classic vehicle during the past 10 years, so chances are the tires will look pretty fresh, especially if your car or truck is garage-kept, which most are. But with old tires, looks can be deceiving – good tread depth does not mean the tire is still good. 

It might be heartbreaking to throw away what looks like a perfectly good set of Pirellis or Goodyear Eagles, but consider the fact that tires are made of rubber and rubber rots over time, like an old rubber band that cracks and breaks when you try to stretch it. 

This is one of the facts of life when it comes to classic cars and other vehicles that are infrequently driven, such as motorhomes and campers, and that old pickup truck you leave up at the cabin. Time and dry rot are tire killers that can’t be avoided, and while the tires might not have too many miles on them, they still need to go.

Tire pros say there can be hidden damage in older tires that risk having them come apart on the highway.

“Even though a 10-year-old tire might look good, you still can’t see what’s inside,” said Marc Strauss, a regional manager for Purcell Tire and Service. “You can’t see the condition of the belts or the plies that are inside that tire.

“They get to a certain age, they dry out and can come apart.”

This is generally not a problem with daily drivers — vehicles that are used for commuting, running errands, going on road trips — all the normal things we do with our regular-use cars, trucks and SUVs. These vehicles clock 12,000 to 15,000 miles per year, on average, so their tires are lucky to last five or six years before the tread wears out, long before they get too old to simply go bad.

But for any rarely used vehicle – classic or otherwise – that spends most of its life relaxing in the garage or under the carport, the time comes when you have to bite the bullet, trash your perfectly good-looking old tires and buy new ones.

Don’t forget that spare, which has been broiling in your trunk for who knows how many years. You might need it sometime.

Although there is no clear industry standard regarding tire age and replacement, most pros recommend changing tires before they reach 10 years old — some say six years is the maximum. Basically, if your tires are aged, you need to consider replacing them no matter how low the mileage.  

Checking the date of manufacture for your tires is easy since there’s a date code on each one, mandated by the federal Department of Transportation. Since 2000, the code is a four-digit number imprinted on the sidewall separate from the other numeric code. The first two numbers designate the week the tire was made, while the second two numbers are the year. 

So the number 2516 would mean that the tire was produced in the 25th week of 2016.  Simple and easy to check.

Still, industry standard is to measure the age of your tires from when they were installed on the vehicle, Strauss said, rather than the actual date of manufacture, so you should keep a record of when you put them on.

Strauss said that one of the most important things to do as your tires age is to have them inspected by a tire professional who knows what to look for and has the ability of checking them over thoroughly and completely.

“A good rule of thumb, and for the classic car world in particular, is to get your tires visually inspected by a tire professional every five or six years whatever the mileage,” Strauss said. “This can determine whether they should be replaced.

“You want to take it to a professional because we can lift the vehicle and do a complete inspection of the tires.  You get to see the condition of the whole tread face and the inside wall of that tire. You have to spin that tire all around, that’s critical, to get an accurate reading.”

What the tire inspectors are look for are small cracks and other signs of the rubber during out, Strauss said, as well as indications of internal damage that show in the tire being out of round or shimmying.

“We’re looking for a couple of things,” he said. “Cracking around the bead area, that’s a big concern. Any time of splitting or cracking there, that’s the biggest indicator of tire failure. Cracks in the tread blocks and the tread grooves are also a concern, but not as big.

“We’re also looking for chunking. When the rubber gets dry and brittle, it will start to chunk or flake off.”

Tire manufacturers are moving away from supplying time-frame warranties because of all the variation of use and climate that can affect a tire’s useful life, Strauss noted. Extreme heat and extreme cold cause the rubber to get brittle faster, and poor maintenance such as running tires underinflated can cause them to fail earlier. 

“You have to make sure you maintain the right pressure, especially if you drive on a tire with low pressure, it generates so much more heat,” he said.  “The worst thing for a tire is to drive on it underinflated.  The biggest killer of a tire is heat, and what makes them heat up fastest is low pressure.”

As you venture out for the classic car driving season, filled with long drives and rallies, make sure that you’ve taken care of the most important piece of safety equipment on your vehicle: its tires. If there is any doubt at all about their age or condition, get them checked out by somebody in the tire business.