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Car care guide · Michigan City Ford · Michigan City, IN
Tire Tread Depth: How Much Is Enough?
Tire tread depth is usually given in 32nds of an inch. With lake effect snow season on the way in Northwest Indiana, here is the minimum depth NHTSA gives, how to check your tires with the wear bars or a penny, and what else to look for.
2/32 inchNHTSA: replace tires worn down to this depth
1/16 inchthe same limit, as NHTSA's booklet puts it
MonthlyNHTSA: check tread when you check pressure
6 to 10 yearsage at which some makers recommend replacement
The short answer
NHTSA says tires are not safe and should be replaced when the tread is worn down to 2/32 of an inch, the same as 1/16 inch. Tires also have built-in treadwear indicators, and NHTSA describes a quick penny test: if you can see the top of Lincoln's head, replace your tires.
The minimum tread depth
NHTSA says tires are not safe and should be replaced when the tread is worn down to 2/32 of an inch. Its tire safety booklet puts the same limit as 1/16 of an inch; 2/32 and 1/16 are the same depth.
Tread is measured in 32nds of an inch, so a reading of 4/32 means four thirty-seconds of an inch of tread left above the bottom of the groove. That is the depth this guide means whenever it gives a fraction.
From NHTSA, Tire Safety Ratings and Awareness (nhtsa.gov) and the NHTSA tire safety booklet (DOT HS 809 361), read November 2, 2026.
How to check your tread depth
NHTSA recommends checking your tread at least once a month, when you check your tire pressure. Ways to check it:
Look for the wear bars
Tires have built-in treadwear indicators: raised sections that run in between the tire's tread. When the tread is worn down so it is level with those indicators, NHTSA says it is time to replace the tire.
Try the penny test
Place a penny in the tread with Lincoln's head upside down and facing you. If you can see the top of Lincoln's head, NHTSA says to replace your tires.
Look for other damage
NHTSA's booklet suggests inspecting tires for uneven wear patterns on the tread, cracks, foreign objects or other signs of wear or trauma.
Know when to stop using a tire
NHTSA says to stop using tires that show signs of physical damage such as cuts, cracks or bulges, or irregular wear or other damage from underinflation or overloading.
From NHTSA, Tire Safety Ratings and Awareness and the NHTSA tire safety booklet (DOT HS 809 361), read November 2, 2026.
Why tread depth matters
NHTSA explains that tire tread provides the gripping action and traction that keep your car or truck from slipping and sliding, especially when the road is icy or wet. That is why worn tread is a safety issue, not just a cosmetic one.
How fast tread wears depends partly on the tire. NHTSA says that the higher a tire's treadwear grade, the longer the tread should take to wear down; for example, a tire graded 200 should wear twice as long as the control tire. Even with tread left, NHTSA notes that some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear.
From NHTSA, Tire Safety Ratings and Awareness, read November 2, 2026.
Service at Michigan City Ford
The Works® at Michigan City Ford includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check. For tire details, see our Ford tire service page.
Schedule service online and see our service specials first. Michigan City Ford is at 3930 Franklin St. in Michigan City. Get directions.
Michigan City Ford service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7:30 a.m.-5:30 p.m. |
| Sat | 8 a.m.-3 p.m. |
| Sun | closed |
From Michigan City Ford's website, November 2, 2026. Holiday hours can differ.
Tire tread depth FAQ
What is the minimum safe tire tread depth?
NHTSA says tires are not safe and should be replaced when the tread is worn down to 2/32 of an inch (1/16 inch).
How do I do the penny test?
Place a penny in the tread with Lincoln's head upside down and facing you. If you can see the top of Lincoln's head, NHTSA says to replace your tires.
What are tread wear indicators?
Raised sections built into the tire that run in between the tread. When the tread is worn down level with them, NHTSA says it is time to replace the tire.
How often should I check my tire tread?
NHTSA recommends checking your tread at least once a month, when you check your tire pressure.
Is 4/32 tread depth OK?
4/32 inch is above the 2/32-inch point at which NHTSA says to replace tires, but the tread is getting closer to that limit. Keep checking monthly, and remember that some vehicle and tire makers also recommend replacing tires at six to 10 years old regardless of treadwear.
What does The Works at Michigan City Ford include?
The Works® at Michigan City Ford includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Tread looking thin?
Book The Works, which includes a tire rotation and pressure check, brake inspection and Multi-Point Inspection, at Michigan City Ford.
Sources
Tread depth limits, checks and tire facts are from NHTSA's tire safety page and booklet, read November 2, 2026. Service details, address and hours are from Michigan City Ford's own website, checked the same day. Photo is illustrative.
- NHTSA, Tire Safety Ratings and Awareness, NHTSA, read November 2, 2026
- NHTSA tire safety booklet (DOT HS 809 361), NHTSA, read November 2, 2026
- Ford tire service in Michigan City, Michigan City Ford, November 2, 2026
- General service: The Works, Michigan City Ford, November 2, 2026
- Address and hours (structured data), Michigan City Ford, November 2, 2026