You can use several methods to check if your vehicle's tires need replacing:
- Tread Wear Indicator Bars (TWI): Most tires have built-in tread wear indicator bars, which are small raised bars within the grooves of the tire tread. When the tread wears down to the level of these bars (usually about 1.6 mm or 2/32 inch), it indicates the tire needs replacing
- Penny Test: Insert a penny into the tire tread with Lincoln’s head upside down. If you can see the top of Lincoln’s head, the tread depth is at or below 2/32 inch, meaning the tire should be replaced. If the head is partially covered, the tread is still sufficient
- Tread Depth Gauge: A precise way to measure tread depth is using a tread depth gauge, which can be a simple ruler marked in 1/32 inch increments or a specialized tool. Tires should be replaced when tread depth is at or below 2/32 inch (about 1.6 mm)
- Replacement Tyre Monitor (RTM): Some modern tires have an RTM inscription that changes to "Replace Tyre" when the tread is worn to the minimum safe level
- Visual Inspection for Uneven Wear: Check for uneven tread wear, which can indicate issues like improper inflation or misalignment. Even if some parts of the tread are above the limit, uneven wear can necessitate replacement
- Advanced Methods: For professional or manufacturing settings, laser tire tread depth gauges like the ProTrak G use 2D laser triangulation to scan the tread profile accurately
In summary, the most common and practical ways to check tire wear at home are the tread wear indicator bars, the penny test, and using a tread depth gauge. When the tread reaches 2/32 inch or the wear bars are flush with the tread, it's time to replace your tires for safety
