235/30R20 tire size
235/30R20 is a metric size: 25.6" tall, 9.3" wide, on a 20" rim — about a 25.5x9.50R20. The sidewall is 2.8" and the tire turns 789 times per mile.
235/30R20 specs
| Overall diameter (height) | 25.55" · 649 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 2.78" · 71 mm (30% of width) |
| Rim diameter | 20" |
| Circumference | 80.27" · 2.039 m |
| Revolutions per mile | 789 (490 per km) |
| Inch (flotation) equivalent | 25.5x9.50R20 |
Equivalent sizes on a 20" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 245/35R20 common | 26.75" | +4.70% | +10 mm | 62.8 mph | compare → |
| 285/30R20 common | 26.73" | +4.62% | +50 mm | 62.8 mph | compare → |
| 275/30R20 common | 26.50" | +3.70% | +40 mm | 62.2 mph | compare → |
| 235/35R20 | 26.48" | +3.62% | 0 mm | 62.2 mph | compare → |
| 245/30R20 | 25.79" | +0.92% | +10 mm | 60.6 mph | compare → |
| 265/30R20 | 26.26" | +2.77% | +30 mm | 61.7 mph | compare → |
| 255/30R20 | 26.02" | +1.85% | +20 mm | 61.1 mph | compare → |
| 225/35R20 | 26.20" | +2.54% | -10 mm | 61.5 mph | compare → |
| 335/25R20 | 26.59" | +4.08% | +100 mm | 62.4 mph | compare → |
| 305/25R20 | 26.00" | +1.77% | +70 mm | 61.1 mph | compare → |
| 295/25R20 | 25.81" | +1.00% | +60 mm | 60.6 mph | calculate → |
| 325/25R20 | 26.40" | +3.31% | +90 mm | 62.0 mph | calculate → |
| 285/25R20 | 25.61" | +0.23% | +50 mm | 60.1 mph | calculate → |
| 225/30R20 | 25.31" | -0.92% | -10 mm | 59.4 mph | calculate → |
| 345/25R20 | 26.79" | +4.85% | +110 mm | 62.9 mph | calculate → |
| 275/25R20 | 25.41" | -0.54% | +40 mm | 59.7 mph | calculate → |
| 215/30R20 | 25.08" | -1.85% | -20 mm | 58.9 mph | calculate → |
| 315/25R20 | 26.20" | +2.54% | +80 mm | 61.5 mph | calculate → |
Plus / minus sizing: 19" and 21" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
Try another size against 235/30R20
Questions
What size is 235/30R20 in inches?
235/30R20 is about 25.6" tall and 9.3" wide on a 20-inch rim — roughly a 25.5x9.50R20 in inch sizing.
What does 235/30R20 mean?
235 mm section width, sidewall 30% of the width (2.78"), radial construction, 20-inch rim.
What tire sizes are equivalent to 235/30R20?
On the same 20" rim, within 3% of the diameter: 285/25R20 (+0.23%), 275/25R20 (-0.54%), 225/30R20 (-0.92%), 245/30R20 (+0.92%), 295/25R20 (+1.00%), 305/25R20 (+1.77%).
How many revolutions per mile does a 235/30R20 tire make?
About 789 revolutions per mile (circumference 80.3").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.