36.5" tall, 12.8" wide, 10.2" sidewall
A 325/80R16 tire is 36.5 inches (926 mm) tall and 12.8 inches wide. The sidewall is 80% of the width, 10.2 inches, on a 16-inch wheel, and the tire turns about 553 times per mile.
In flotation terms that is about 36.5x12.8R16. People often call it a 36-inch tire.
The size most often compared with it is 315/80R16, which is 0.6" shorter (−1.7%). At an indicated 60 mph you would be doing 59.0 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 325/80R16 | |
|---|---|---|---|---|---|
| 315/80R16 | 35.8" | 12.4" | 9.9" | −1.7% | |
| 325/75R16 | 35.2" | 12.8" | 9.6" | −3.5% | |
| 315/75R16 | 34.6" | 12.4" | 9.3" | −5.1% | |
| 305/75R16 | 34.0" | 12.0" | 9.0" | −6.7% | |
| 315/70R16 | 33.4" | 12.4" | 8.7" | −8.5% | |
| 305/70R16 | 32.8" | 12.0" | 8.4" | −10.0% |
Sizes within 2% of 36.5" on 18" or 17" wheels.
| Size | Diameter | Width | Sidewall | vs 325/80R16 | |
|---|---|---|---|---|---|
| 275/85R18 | 36.4" | 10.8" | 9.2" | −0.2% | |
| 285/85R17 | 36.1" | 11.2" | 9.5" | −1.1% | |
| 305/75R18 | 36.0" | 12.0" | 9.0" | −1.3% | |
| 285/80R18 | 36.0" | 11.2" | 9.0" | −1.4% | |
| 37x12.50R17 | 37.0" | 12.5" | 10.0" | +1.4% | |
| 37x12.50R18 | 37.0" | 12.5" | 9.5" | +1.4% |
Actual speed when the speedometer is calibrated for 325/80R16.
| Speedometer shows | on 315/80R16 | on 325/75R16 | on 315/75R16 |
|---|---|---|---|
| 30 mph | 29.5 mph | 28.9 mph | 28.5 mph |
| 45 mph | 44.2 mph | 43.4 mph | 42.7 mph |
| 60 mph | 59.0 mph | 57.9 mph | 56.9 mph |
| 70 mph | 68.8 mph | 67.5 mph | 66.4 mph |
36.5 inches (926 mm). The sidewall is 10.2 inches.
12.8 inches (325 mm) section width, measured sidewall to sidewall.
About 36.5x12.8R16.
315/80R16 is −1.7% in diameter, within the common 3% guideline. It is 0.4" narrower.