Things You'll Need:
- Ruler
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Step 1
Examine your tires for the tread wear indicators. They are bars made of hard rubber lying crossways across the tread. You can't see them on new tires, but as the tread wears down, they become visible.
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Step 2
Count the number of the tread wear indicators which are visible, as well as their dispersal across the surface of the tire. If you can see them in more than two places and/or they are less than 120 degrees apart on the circumference of the tire, then the tire has worn out and you should replace it as soon as possible.
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Step 3
Use your tire marks to spot the indicators. Wet your tires down with a little water, then drive forward over a dry patch of parking lot. Get out of the car and examine the marks left behind by the tires. If you can see horizontal bars cutting across the pattern, the tread wear indicators are visible and the tires should be replaced immediately.
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Step 4
Measure the depth of the tread with a ruler. It should be more than 1/16 of an inch. Tread wear indicators appear when the tread has worn down to 1/16 of an inch. If it is higher than 1/16 of an inch, but is getting close to that mark, you should think about getting new tires soon. If it is less than that, then you should replace the tires immediately.
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Step 5
Check all of your tires when the tread wear indicator appears on them. You generally want to replace all of your tires at once (or at least the two front ones and the two back ones at the same time). If the tread wear indicators show up on one, there's a good chance they are showing or close to showing on all of them.
