The 1:16-Inch Rule
Most people wait until their tires "look" bald to replace them. The problem? By the time a tire looks bald, it has likely been unsafe for months. In the industry, we use the standard of 2/32" (about 1.6mm) as the legal limit for tread depth.
If you don't have a professional depth gauge in your glovebox, you have a replacement in your pocket: a penny.
How to Perform the Test
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The Setup: Take a standard copper penny and hold it between your thumb and forefinger.
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The Placement: Insert the penny into one of the main tread grooves of your tire with Lincoln’s head pointing down into the rubber.
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The Result: * If you can see the top of Lincoln’s head: Your tread is shallower than 2/32". Your tires are legally "bald" and your stopping distance—especially in the rain—is severely compromised. It is time to replace them.
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If the tread covers part of his head: You have a bit of life left, but you should start planning your next set.
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Why "Legal" Isn't Always "Safe"
At our shop, we prefer the Quarter Test. While a penny measures the legal limit, a quarter (aiming for the top of Washington's head) measures 4/32".
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Wet Roads: If you drive in a climate with heavy rain, 2/32" isn't enough to clear water from under the tire, which leads to hydroplaning.
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Snow & Dirt: If you’re running off-road or winter tires, you actually want to look for replacement closer to 6/32" to maintain grip in loose material.
The "Pro" Tip: Check the Wear Bars
While you’re down there with your penny, look for the Tread Wear Indicator Bars. These are small horizontal bridges of rubber buried deep in the grooves. When the rest of your tread is flush with these bars, the tire is finished.
Straight-Talk: Tires are the only thing connecting your vehicle to the pavement. If Lincoln is staring back at you, don't wait for a rainy day to find out how little grip you have left.
Ready for a Fresh Set?
If your penny test failed, browse our Fitment Gallery to see how a new set of deep-tread rubber looks on a rig like yours. We ship fresh DOT-dated tires directly to your door so you don't have to guess about your safety.