How do I monitor my tire’s tread?
Excessive tire tread wear will reduce steering and braking response to your vehicle. It’s important to monitor the tire’s tread on a monthly basis and to replace your auto tires when needed depending on the wear of the tread to avoid blowouts or flat tires. Auto Tires worn down past their safety margins and into the casing run the very real risk of rupturing.
A US penny can be used to check tire tread to see if it is down to 1/16 or 2/32 of an inch.
1. Take a penny and put Lincoln’s head into one of the grooves of the tire tread.
2. If part of his head is covered by the tread, you are driving with the legal amount of tread.
3. If you can see all of Lincoln’s head, it is time to replace the tire.
Similar size coins to the US penny (which has a diameter of .75 inches), of other currencies with heads on one side, can also be used, depending on the legal minimum tire requirements of each individual country. However, a much more useful test, for those outside of the USA, is to insert the head of an unused match into the tire’s tread; if the tread is at any point below 3/4 of the head, the tire should be replaced.
US and European tires have ‘wear bars’, or “Tread Wear Indicators” (TWI) moulded into the grooves of the tire. When these become flush with the tops of the remaining tread, the tire is at the legal limit of normal safety and must be replaced. Certain European countries have stricter limits on tread wear compared to other European countries.
The November 2007 issue of “Consumer Reports” magazine, (page 60), stated that based on tests they conducted; tires should be replaced when the tire tread is down to 1/8 inch. This is about the distance to George Washington’s hairline on a US quarter. The tire that just passes the “penny test” could be dangerous when driving in snow or when hydroplaning.
Also it’s recommended to have a professional tire replacement company familiar with tires and wheel packages to review and replace any tire that you have questions about driving on.