Guide
On this page
- When to replace by tread depth
- The penny test
- The quarter test (better)
- Tread wear indicators (built-in)
- Tread depth gauge
- When to replace by age
- How to find tire age
- When to replace by damage
- Sidewall damage
- Tread damage
- Uneven wear
- Replace as a set or in pairs
- Front-wheel-drive vehicles
- Rear-wheel-drive vehicles
- All-wheel-drive vehicles
- When all four are similar wear
- Cost breakdown
- Tire cost by quality tier
- Plus installation costs
- Tire selection considerations
- Match the original size
- Match purpose
- Quality brands
- Related guides
When to Replace Tires
When to replace by tread depth
The penny test
Insert a penny into the tread groove, Lincoln's head down. If you can see the top of Lincoln's head, your tread is below 2/32 inch — legally bald in most states.
The quarter test (better)
Insert a quarter, Washington's head down. If you can see the top of Washington's head, your tread is below 4/32 inch — replace soon, especially for wet weather.
Tread wear indicators (built-in)
Most tires have small raised bars in the tread grooves. When the bars are flush with the tread surface, you're at 2/32 inch.
Tread depth gauge
A digital gauge ($5–$15) measures exact depth. Replace at:
- 4/32 inch: if you drive in wet weather frequently.
- 3/32 inch: for any general use.
- 2/32 inch: absolute legal minimum, unsafe in wet.
When to replace by age
Rubber compounds degrade over time even with no wear:
- 6 years from date of manufacture: start inspecting more carefully.
- 10 years from date of manufacture: replace regardless of tread.
How to find tire age
Check the DOT date code on the sidewall. The last 4 digits indicate week and year of manufacture.
Example: DOT XXXXXX 2519 = manufactured 25th week of 2019.
Tires made before 2000 used a 3-digit code, but those should definitely be replaced anyway.
When to replace by damage
Sidewall damage
- Bulges: internal cord broken. Tire can fail catastrophically. Replace immediately.
- Cuts: deeper than 1/8 inch. Replace.
- Cracks: weather cracking on sidewall surface. Inspect by shop.
Tread damage
- Punctures larger than 1/4 inch: can't be repaired. Replace.
- Punctures in the shoulder area (within 1 inch of the sidewall): can't be repaired. Replace.
- Multiple punctures (more than 3): structurally compromised. Replace.
Uneven wear
- Inside or outside edge wear: alignment issue. Fix alignment AND replace if wear is significant.
- Center wear: chronic over-inflation. Adjust PSI; tire may be reusable if uneven wear is modest.
- Edge wear pattern: chronic under-inflation. Same logic.
- Cupping (scallops): worn shocks. Address shocks; replace tires if uneven wear is severe.
Replace as a set or in pairs
Front-wheel-drive vehicles
Replace front tires as a pair when they wear faster. Keep rear tires until they hit replacement threshold separately.
Rear-wheel-drive vehicles
Replace rear tires as a pair when they wear faster.
All-wheel-drive vehicles
Replace all four together. AWD systems require matched tire diameters; mismatched tires cause drivetrain binding and damage to the center differential.
When all four are similar wear
Replace all four for even handling.
Cost breakdown
Tire cost by quality tier
| Tier | Per tire | Set of 4 |
|---|---|---|
| Budget | $80–$120 | $320–$480 |
| Mid-range | $120–$200 | $480–$800 |
| Premium | $200–$350 | $800–$1,400 |
| Performance / luxury | $300–$600 | $1,200–$2,400 |
Plus installation costs
| Service | Cost |
|---|---|
| Mount and balance | $15–$30 per tire |
| Disposal fee | $3–$8 per tire |
| Stem replacement | $3–$6 per tire |
| TPMS rebuild | $5–$20 per tire (sometimes mandatory) |
| Alignment | $80–$160 |
Total typical: $500–$1,500 out the door for a set of four.
Tire selection considerations
Match the original size
OEM size is on the door jamb sticker. Stick with the spec'd size unless you have specific reason to deviate.
Match purpose
- All-season: versatile, year-round adequate.
- Performance summer: sharper grip, no winter capability.
- Winter (M+S + snowflake): dramatically better in snow/ice.
- All-terrain: truck/SUV off-road capability.
- Mud-terrain: off-road heavy.
Quality brands
Premium: Michelin, Bridgestone, Continental, Pirelli. Mid-range: Goodyear, Hankook, Toyo, Yokohama. Budget: Kumho, Falken, Cooper. Avoid: unknown Chinese brands with no reputation.