What is the minimum tread depth in millimeters for not needing to replace tires?
3 Answers
Tires do not need to be replaced if the tread depth is not less than 1.6 millimeters, but they should be replaced if the depth is greater than 1.6 millimeters. Tires should not continue to be used under the following conditions. Tire wear: Tires have tread wear indicators, which are slightly raised marks located at the bottom of the tread grooves with a height of 1.6 millimeters (the legal minimum groove depth). If the tread rubber wears down to the same level as these raised indicators, the tires should be replaced immediately, as continued driving is no longer safe. Using worn tires on wet or slippery roads can lead to "hydroplaning," increasing the risk of losing control of the vehicle. This is because excessively worn treads cannot effectively channel water away from under the tires, potentially causing loss of control. Tire damage: Hitting curbs, falling into potholes, or punctures from nails can severely damage tires. Damaged tires may sometimes be repairable, but only a professional repair shop can accurately determine whether a tire can be repaired or must be replaced. Generally, sidewall damage cannot be repaired, and for safety reasons, the tire must be replaced.
From my over ten years of experience in car repair, the tread depth of tires should be maintained at least above 1.6 millimeters, otherwise it's time to replace them. Once, a customer didn't change their tires when the tread was only 1.5 millimeters left, and ended up skidding and hitting the curb while turning on a rainy day. I often remind people not to underestimate this number—below 1.6 millimeters, the grip significantly deteriorates, especially on wet roads where the braking distance can increase several times. Checking it is simple: insert a one-yuan coin into the tread; if the outer ring of the coin is completely visible, the tread depth is definitely insufficient. Also, consider your driving habits—for example, cars frequently driven on highways or carrying heavy loads need to pay more attention to faster tread wear. Regularly check the depth during maintenance; spending some money on new tires is much more cost-effective and worry-free than dealing with an accident.
As a car enthusiast, I always check my tire conditions before heading out. Generally, tires must be replaced when the tread depth falls below 1.6mm—I learned this the hard way last year when I nearly slid off a mountain road. Safety comes first, as tread depth directly affects wet-weather drainage performance. Tires with treads deeper than 1.6mm can effectively channel water away, maintaining grip. Shallow treads make it easy to lose control during turns or sudden braking. I recommend using a professional tread depth gauge or even a simple ruler for a quick check. Don’t wait for the warning light—inspect them every six months in advance. Also, tire brands and road conditions affect wear rates; for example, rough terrain wears treads faster, so replacing them early is wiser.
