Tires degrade over time due to environmental exposure, regardless of how much tread is left. How to Buy Tires: A Step-by-Step Guide - US News Cars
For a stricter safety margin, use a quarter. If Washington's head is fully visible, your tread is below 4/32", and you should plan for a replacement soon. when to buy new tires
Many experts, including Tire Rack and SimpleTire , recommend replacing tires at 4/32" , especially if you drive in wet or snowy conditions where traction drops significantly below this point. Quick DIY Tests Tires degrade over time due to environmental exposure,
Insert a penny upside down into the tread. If you can see the top of Lincoln's head, your tread is below 2/32" and the tire is unsafe. your tread is below 4/32"