Safety Tips for Buying Used Tires

a perspective view of a rack of used tires ready for sale
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Used tires are a huge business in this country. Somewhere around 30 million used tires are sold each year, constituting about 10 percent of the total US tire market. It's not a surprise that many people find buying used tires to be a pretty good deal, usually to replace a single tire that's been damaged. But something that looks like a great deal can sometimes turn out to be too good to be true.

Problems With Used Tire Sales

The problem is this: Used tires are not subject to any kind of legal standards, and the process of collecting, inspecting and reinserting used tires into the market varies rather widely. Some used tire sellers are careful experts who closely inspect their inventory to make sure their tires are safe. But many others are not so careful.

In 1989, a former manager for Michelin named Clarence Ball conducted an informal survey of used tires for sale near him and published his results. He concluded: “My worst fears were realized when I found a number of tires that looked good – until I examined inside. I doubt that the tire fitter or customer would have spotted loose cords in the tires, evidence that they had been run while underinflated. Several tires had tread repairs which would have caused a number of weights to be used in an attempt to balance them and a few had puncture repairs that looked like they had been done by a plumber.”

The issue has not improved with time. Just a few years ago, the Rubber Manufacturers Association tested the used tire market in Texas by purchasing a number of tires from used tire stores. The vast majority were unsafe in some way, whether simply worn out, showing visible damage or improperly repaired. The RMA's Senior Vice President Dan Zielinski commented, “Unsafe used tires are readily available for sale across the nation. Any used tire is a risky proposition since it’s impossible to know the service history of a tire used by someone else. But some businesses are compounding that problem by selling tires that anyone in the tire business should know are dangerous.”

To combat the problem, both the Rubber Manufacturer's Association and the Tire Industry Association have recently thrown their support behind efforts in both Texas and Florida to ban the sale of unsafe used tires, and at this time it looks as if both state bills will easily become law.

The bills essentially ban the sale of any tire which:

  • Has tire tread less than 2/32-inch deep
  • Has chunking, bumps, knots, or bulges evidencing cord, ply or tread separation from the casing or other adjacent material
  • Has exposed tire cords or belting material as a result of damage to the tire
  • Has a repair to the tire in the tread shoulder, sidewall, bead area or belt edge area
  • Has a puncture that has not been sealed or patched on the inside with a cured rubber stem or plug that extends through to the outside surface
  • Does not clearly show the United States Department of Transportation tire identification number located on the sidewall of the tire
  • Is subject to a manufacturer's safety recall
  • Has a puncture larger than one-quarter inch

So there are a great many potential problems with a used tire, and since it is clear that many sellers of used tires pay far too little attention to these issues, this means that buyers of used tires need to have a lot more information in order to know what's safe and what is clearly not. Even in states where it may soon be against the law to sell unsafe tires, some sellers will always be ignorant of the law or unwilling to follow it, so that the law of Buyer Beware clearly applies no matter where you live. I'm here to help.

Things to Look Out for When Buying Used Tires

If you're going to buy a used tire, these are the things to look for:

  • Tread Depth: Make sure to bring a penny with you when you go to buy a used tire, so you can do the penny test. Put the penny upside-down into one or more of the tire's grooves. If you can see all of Lincoln's head, the tire is legally bald and you shouldn't be driving on it.
  • Exposed Cords: Look carefully at the tread surface all around. Irregular wear can expose the braided steel cords inside the tire. If you can see the cords, or even a few thin steel wires coming out of the tread, the tire is dangerous.
  • Belt Separation: Look closely at the sidewall and tread surface for bumps, waviness or other irregularities that might indicate an impact that has caused the rubber to delaminate from the steel belts. You can often feel changes in the rubber surface by running your hands over the sidewall and tread surface even if the irregularity is not obvious when the tire is not inflated.
  • Bead Chunking: Look closely at the bead areas, the two thick rings of rubber where the tire contacts the wheel. You're looking especially for chunks of rubber missing from the beads, or other damage that can prevent the tire from sealing correctly.
  • Liner Damage: Look inside the tire at the inner liner for damage and/or exposed cords. When a tire begins losing air, the sidewalls begin to collapse. At some point, the collapsing sidewalls will fold over and begin to rub against themselves. This process will scrub the rubber liner off the inside of the sidewalls until the sidewall is damaged beyond repair. If you can see a “stripe” of wear circling around the sidewall of the tire that is softer to the touch than the rest of the sidewall, or if you find “rubber dust”, small particles of rubber inside, or if the sidewall has been worn away until you can see the inner structure, stay away from that tire, as it is unsafe.
  • Improper Repairs: Definitely look for punctures in the tire, but also look inside and out for punctures that have been repaired. A proper repair is a full patch on the inside of the tire. Plugs are not inherently unsafe, but patches are much safer. Definitely avoid large punctures or repaired punctures located within an inch of either sidewall.
  • Aging: Aging tires deteriorate from the inside out, making it difficult to tell how safe they might be. The first thing to do is make sure there is a Tire Identification Number (always preceded by the letters DOT) on the sidewall, as some used tire recyclers and retailers have been known to scrub the number off. If the TIN is present, the first two numbers or letters after the DOT indicate the plant where the tire was manufactured. The next four numbers indicate the date the tire was built, i.e., the number 1210 indicates that the tire was manufactured in the 12th week of 2010. In general, you should be suspicious of any tire that is more than 6 years old. You should also look at the sidewall and tread areas for signs of small cracks appearing at flex points on the sidewall or in between the tread blocks, which may indicate that dry rot has begun to attack the rubber. Keep in mind as well that some people will paint used tires black to make them look newer. Recalls: Use the TIN to check for manufacturer's recalls on the tire.

Final Thoughts

These are the major things to look for when buying a used tire. Remember that even if selling unsafe used tires becomes illegal in your state, it's still primarily your responsibility in a pragmatic sense to ensure that the tire you're buying is safe. That the law can punish a seller of unsafe tires would be cold comfort to you or your family if something bad happens. Be proactive and above all, be safe!