31.1" tall, 8.9" wide, 7.5" sidewall
A 225/85R16 tire is 31.1 inches (789 mm) tall and 8.9 inches wide. The sidewall is 85% of the width, 7.5 inches, on a 16-inch wheel, and the tire turns about 649 times per mile.
In flotation terms that is about 31.1x8.9R16. People often call it a 31-inch tire.
The size most often compared with it is 245/80R16, which is 0.4" taller (+1.2%). At an indicated 60 mph you would be doing 60.7 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 16" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 225/85R16 | |
|---|---|---|---|---|---|
| 245/80R16 | 31.4" | 9.6" | 7.7" | +1.2% | |
| 245/75R16 | 30.5" | 9.6" | 7.2" | −1.9% | |
| 215/85R16 | 30.4" | 8.5" | 7.2" | −2.2% | |
| 235/85R16 | 31.7" | 9.3" | 7.9" | +2.2% | |
| 235/75R16 | 29.9" | 9.3" | 6.9" | −3.8% | |
| 245/85R16 | 32.4" | 9.6" | 8.2" | +4.3% | |
| 215/80R16 | 29.5" | 8.5" | 6.8" | −4.9% | |
| 225/75R16 | 29.3" | 8.9" | 6.6" | −5.7% | |
| 205/80R16 | 28.9" | 8.1" | 6.5" | −6.9% |
Sizes within 2% of 31.1" on 17" or 15" or 18" wheels.
| Size | Diameter | Width | Sidewall | vs 225/85R16 | |
|---|---|---|---|---|---|
| 255/70R17 | 31.1" | 10.0" | 7.0" | −0.0% | |
| 275/65R17 | 31.1" | 10.8" | 7.0" | +0.1% | |
| 31x10.50R15 | 31.0" | 10.5" | 8.0" | −0.2% | |
| 275/60R18 | 31.0" | 10.8" | 6.5" | −0.2% | |
| 225/80R17 | 31.2" | 8.9" | 7.1" | +0.4% | |
| 305/55R18 | 31.2" | 12.0" | 6.6" | +0.5% |
Actual speed when the speedometer is calibrated for 225/85R16.
| Speedometer shows | on 245/80R16 | on 245/75R16 | on 215/85R16 |
|---|---|---|---|
| 30 mph | 30.4 mph | 29.4 mph | 29.4 mph |
| 45 mph | 45.5 mph | 44.1 mph | 44.0 mph |
| 60 mph | 60.7 mph | 58.9 mph | 58.7 mph |
| 70 mph | 70.8 mph | 68.7 mph | 68.5 mph |
31.1 inches (789 mm). The sidewall is 7.5 inches.
8.9 inches (225 mm) section width, measured sidewall to sidewall.
About 31.1x8.9R16.
245/80R16 is +1.2% in diameter, within the common 3% guideline. It is 0.8" wider.