Tires are legally worn out at 2/32 inch tread depth in most states - but safety researchers and Consumer Reports recommend replacement at 4/32. The wet-braking difference is massive. Here is how to measure and decide.
At 2/32 inch tread (legal minimum), wet stopping distance from 60 mph nearly doubles compared to 4/32. If you drive in rain, plan replacement at 4/32, not 2/32.
Insert a penny with Lincoln upside down. If you can see all of Lincoln's head, tread is at or below 2/32 inch - legally worn out in most states.
Insert a quarter with Washington upside down. If you can see all of Washington's head, tread is below 4/32 inch - replacement recommended for wet safety.
Built-in rubber bars in tread grooves. When flush with surrounding tread, the tire is at 2/32 - same as penny test failing.
A $5 gauge from any auto parts store. Measure in the deepest groove. Reads in 32nds of an inch (or mm).
Premium tires have built-in indicators (Michelin Premier Tx, Nokian) that fade as the tire wears. Visual cue to plan replacement.
| Depth | Status & Recommendation |
|---|---|
| 10-11/32" | New tire (most all-seasons) |
| 8-9/32" | Excellent, no concern |
| 6-7/32" | Good - normal mid-life |
| 5/32" | Plan replacement within 6-12 months |
| 4/32" | Wet performance dropping - replace soon |
| 3/32" | Wet braking compromised significantly |
| 2/32" | Legal minimum - replace now |
| Below 2/32" | Illegal in most states - do not drive |
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2/32 inch (1.6 mm) in most US states. Below that, the tire fails state inspection and is technically not roadworthy. Some states have lower minimums for trailers but cars are 2/32.
4/32 inch or more. At 2/32 inch, wet stopping distance from 60 mph nearly doubles vs new tires. Consumer Reports, NHTSA, and most tire makers recommend replacing at 4/32 for wet driving safety.
Insert a penny into the deepest tread groove with Lincoln's head upside down and facing you. If you can see all of Lincoln's head, tread is at or below 2/32 inch - replace immediately.
Same idea but with a quarter and Washington. If you can see all of Washington's head, tread is at or below 4/32 inch - plan replacement for wet safety.
Every oil change (5000-7500 miles), or before any long trip. Also after any tire repair or rotation, to confirm even wear.
Yes. Tire age matters as much as tread. Rubber degrades 6-10 years from manufacture regardless of mileage. Cracks, hardening, and unpredictable failure follow.