29.0" tall, 12.8" wide, 4.5" sidewall
A 325/35R20 tire is 29.0 inches (736 mm) tall and 12.8 inches wide. The sidewall is 35% of the width, 4.5 inches, on a 20-inch wheel, and the tire turns about 696 times per mile.
In flotation terms that is about 29.0x12.8R20. People often call it a 29-inch tire.
The size most often compared with it is 315/35R20, which is 0.3" shorter (−1.0%). At an indicated 60 mph you would be doing 59.4 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 20" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 325/35R20 | |
|---|---|---|---|---|---|
| 315/35R20 | 28.7" | 12.4" | 4.3" | −1.0% | |
| 305/40R20 | 29.6" | 12.0" | 4.8" | +2.2% | |
| 345/30R20 | 28.1" | 13.6" | 4.1" | −2.8% | |
| 315/40R20 | 29.9" | 12.4" | 5.0" | +3.3% | |
| 305/30R20 | 27.2" | 12.0" | 3.6" | −6.1% | |
| 305/45R20 | 30.8" | 12.0" | 5.4" | +6.4% | |
| 315/45R20 | 31.2" | 12.4" | 5.6" | +7.6% |
Sizes within 2% of 29.0" on 22" or 18" wheels.
| Size | Diameter | Width | Sidewall | vs 325/35R20 | |
|---|---|---|---|---|---|
| 295/30R22 | 29.0" | 11.6" | 3.5" | +0.0% | |
| 255/35R22 | 29.0" | 10.0" | 3.5" | +0.2% | |
| 275/50R18 | 28.8" | 10.8" | 5.4" | −0.4% | |
| 305/30R22 | 29.2" | 12.0" | 3.6" | +0.9% | |
| 285/50R18 | 29.2" | 11.2" | 5.6" | +0.9% | |
| 315/30R22 | 29.4" | 12.4" | 3.7" | +1.7% |
Actual speed when the speedometer is calibrated for 325/35R20.
| Speedometer shows | on 315/35R20 | on 305/40R20 | on 345/30R20 |
|---|---|---|---|
| 30 mph | 29.7 mph | 30.7 mph | 29.2 mph |
| 45 mph | 44.6 mph | 46.0 mph | 43.7 mph |
| 60 mph | 59.4 mph | 61.3 mph | 58.3 mph |
| 70 mph | 69.3 mph | 71.6 mph | 68.0 mph |
29.0 inches (736 mm). The sidewall is 4.5 inches.
12.8 inches (325 mm) section width, measured sidewall to sidewall.
About 29.0x12.8R20.
315/35R20 is −1.0% in diameter, within the common 3% guideline. It is 0.4" narrower.