How is tire tread depth measured?
Tread depth is the distance from the top of the tread to the bottom of the deepest groove, measured in 32nds of an inch in the US.
Many new passenger tires start at around 10/32 to 11/32 in, though it varies by tire. A tread depth gauge, sold at most auto parts stores, gives you an exact reading.
Measure in the main grooves at the inner, center and outer parts of the tread, and in a few spots around the tire. Use the lowest reading.
What is the legal minimum tread depth in New York?
New York State inspection requires at least 2/32 in of tread. A tire below that fails inspection.
Two thirty-seconds is the floor, not a target. Grip on wet and snowy roads drops well before a tire reaches it.
How do I do the penny test?
Put a penny upside down into a main tread groove with Lincoln’s head pointing in. If you can see all of his head, the tread is at or below 2/32 in.
Try it in several grooves and spots around the tire. Tires often wear unevenly, so one good reading does not clear the whole tire.
How do I do the quarter test?
Put a quarter upside down into the groove with Washington’s head pointing in. If the tread touches the top of his head, you have about 4/32 in or more.
If you can see all of Washington’s head, you have less than about 4/32 in. Many tire experts suggest planning to replace tires around that point if you often drive in rain or snow.
What are tread wear indicator bars?
They are small raised bars of rubber molded across the bottom of the main grooves at 2/32 in.
When the tread wears down flush with those bars, the tire is at the minimum and should be replaced. Some tires also mark the bar locations with a small triangle or symbol on the shoulder.
Why does tread depth matter in rain and snow?
The grooves move water and slush out from under the tire. As they get shallower, the tire can float on a layer of water, which is called hydroplaning, and stopping distances get longer.
That is why a tire with legal tread can still feel slippery in a storm. If your tires are getting close to 4/32 in and winter is coming, it is a good time to look at replacements. Message us your tire size.
Quick answers
How much tread is left on new tires?
Many new passenger tires start at around 10/32 to 11/32 in, though it varies by tire. Truck and winter tires often start deeper.
Is 4/32 tread depth safe?
It is legal in New York, but wet and snow grip are reduced at that depth. Many tire experts suggest planning to replace tires around 4/32 in if you drive often in bad weather.
Why is one side of my tire more worn than the other?
Uneven wear usually points to alignment, suspension or tire pressure issues. Measure both edges, and have the cause checked so new tires do not wear the same way.
Can you check my tread depth?
Yes. Stop by the shop and we will measure your tires and show you the readings.