235/55R20 tire size
235/55R20 is a metric size: 30.2" tall, 9.3" wide, on a 20" rim — about a 30x9.50R20. The sidewall is 5.1" and the tire turns 668 times per mile.
235/55R20 specs
| Overall diameter (height) | 30.18" · 767 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 5.09" · 129 mm (55% of width) |
| Rim diameter | 20" |
| Circumference | 94.80" · 2.408 m |
| Revolutions per mile | 668 (415 per km) |
| Inch (flotation) equivalent | 30x9.50R20 |
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 | |
|---|---|---|---|---|---|
| 245/45R20 common | 28.68" | -4.96% | +10 mm | 57.0 mph | compare → |
| 255/45R20 common | 29.04" | -3.78% | +20 mm | 57.7 mph | compare → |
| 255/50R20 common | 30.04" | -0.46% | +20 mm | 59.7 mph | compare → |
| 265/50R20 common | 30.43" | +0.85% | +30 mm | 60.5 mph | compare → |
| 245/50R20 common | 29.65" | -1.76% | +10 mm | 58.9 mph | compare → |
| 275/45R20 common | 29.74" | -1.44% | +40 mm | 59.1 mph | compare → |
| 255/55R20 common | 31.04" | +2.87% | +20 mm | 61.7 mph | compare → |
| 265/45R20 common | 29.39" | -2.61% | +30 mm | 58.4 mph | compare → |
| 315/35R20 common | 28.68" | -4.96% | +80 mm | 57.0 mph | compare → |
| 275/50R20 common | 30.83" | +2.15% | +40 mm | 61.3 mph | compare → |
| 295/40R20 | 29.29" | -2.94% | +60 mm | 58.2 mph | compare → |
| 285/50R20 | 31.22" | +3.46% | +50 mm | 62.1 mph | compare → |
| 285/40R20 | 28.98" | -3.98% | +50 mm | 57.6 mph | compare → |
| 245/60R20 | 31.57" | +4.63% | +10 mm | 62.8 mph | compare → |
| 235/50R20 | 29.25" | -3.07% | 0 mm | 58.2 mph | compare → |
| 285/45R20 | 30.10" | -0.26% | +50 mm | 59.8 mph | compare → |
| 295/45R20 | 30.45" | +0.91% | +60 mm | 60.5 mph | compare → |
| 305/40R20 | 29.61" | -1.89% | +70 mm | 58.9 mph | compare → |
| 235/60R20 | 31.10" | +3.07% | 0 mm | 61.8 mph | calculate → |
| 325/35R20 | 28.96" | -4.04% | +90 mm | 57.6 mph | calculate → |
| 305/45R20 | 30.81" | +2.09% | +70 mm | 61.3 mph | calculate → |
| 31x18.00R20 | 31.00" | +2.73% | +222 mm | 61.6 mph | calculate → |
| 29x15.00R20 | 29.00" | -3.90% | +146 mm | 57.7 mph | calculate → |
| 29x18.00R20 | 29.00" | -3.90% | +222 mm | 57.7 mph | calculate → |
| 265/55R20 | 31.48" | +4.31% | +30 mm | 62.6 mph | calculate → |
| 175/70R20 | 29.65" | -1.76% | -60 mm | 58.9 mph | calculate → |
| 295/50R20 | 31.61" | +4.76% | +60 mm | 62.9 mph | calculate → |
Plus / minus sizing: 19" and 21" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 255/55R19 common | 30.04" | -0.44% | +20 mm | 59.7 mph | compare → |
| 295/40R21 | 30.29" | +0.38% | +60 mm | 60.2 mph | compare → |
| 285/40R21 | 29.98" | -0.67% | +50 mm | 59.6 mph | compare → |
| 265/45R21 | 30.39" | +0.70% | +30 mm | 60.4 mph | compare → |
| 255/45R21 | 30.04" | -0.47% | +20 mm | 59.7 mph | compare → |
| 265/55R19 | 30.48" | +0.99% | +30 mm | 60.6 mph | compare → |
| 235/50R21 | 30.25" | +0.25% | 0 mm | 60.1 mph | calculate → |
| 235/60R19 | 30.10" | -0.25% | 0 mm | 59.9 mph | calculate → |
| 175/80R19 | 30.02" | -0.51% | -60 mm | 59.7 mph | calculate → |
Try another size against 235/55R20
Questions
What size is 235/55R20 in inches?
235/55R20 is about 30.2" tall and 9.3" wide on a 20-inch rim — roughly a 30x9.50R20 in inch sizing.
What does 235/55R20 mean?
235 mm section width, sidewall 55% of the width (5.09"), radial construction, 20-inch rim.
What tire sizes are equivalent to 235/55R20?
On the same 20" rim, within 3% of the diameter: 285/45R20 (-0.26%), 255/50R20 (-0.46%), 265/50R20 (+0.85%), 295/45R20 (+0.91%), 275/45R20 (-1.44%), 175/70R20 (-1.76%).
How many revolutions per mile does a 235/55R20 tire make?
About 668 revolutions per mile (circumference 94.8").
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.