235/45R20 tire size
235/45R20 is a metric size: 28.3" tall, 9.3" wide, on a 20" rim — about a 28.5x9.50R20. The sidewall is 4.2" and the tire turns 712 times per mile.
235/45R20 specs
| Overall diameter (height) | 28.33" · 720 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 4.16" · 106 mm (45% of width) |
| Rim diameter | 20" |
| Circumference | 88.99" · 2.260 m |
| Revolutions per mile | 712 (442 per km) |
| Inch (flotation) equivalent | 28.5x9.50R20 |
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 | |
|---|---|---|---|---|---|
| 245/45R20 common | 28.68" | +1.25% | +10 mm | 60.8 mph | compare → |
| 255/45R20 common | 29.04" | +2.50% | +20 mm | 61.5 mph | compare → |
| 275/40R20 common | 28.66" | +1.18% | +40 mm | 60.7 mph | compare → |
| 245/40R20 common | 27.72" | -2.15% | +10 mm | 58.7 mph | compare → |
| 245/50R20 common | 29.65" | +4.66% | +10 mm | 62.8 mph | compare → |
| 255/35R20 common | 27.03" | -4.59% | +20 mm | 57.2 mph | compare → |
| 255/40R20 common | 28.03" | -1.04% | +20 mm | 59.4 mph | compare → |
| 275/35R20 common | 27.58" | -2.64% | +40 mm | 58.4 mph | compare → |
| 265/45R20 common | 29.39" | +3.75% | +30 mm | 62.3 mph | compare → |
| 285/35R20 common | 27.85" | -1.67% | +50 mm | 59.0 mph | compare → |
| 315/35R20 common | 28.68" | +1.25% | +80 mm | 60.8 mph | compare → |
| 265/35R20 common | 27.30" | -3.61% | +30 mm | 57.8 mph | compare → |
| 295/30R20 | 26.97" | -4.79% | +60 mm | 57.1 mph | compare → |
| 305/30R20 | 27.20" | -3.96% | +70 mm | 57.6 mph | compare → |
| 295/40R20 | 29.29" | +3.41% | +60 mm | 62.0 mph | compare → |
| 295/35R20 | 28.13" | -0.69% | +60 mm | 59.6 mph | compare → |
| 305/35R20 | 28.41" | +0.28% | +70 mm | 60.2 mph | compare → |
| 285/40R20 | 28.98" | +2.29% | +50 mm | 61.4 mph | compare → |
| 235/50R20 | 29.25" | +3.27% | 0 mm | 62.0 mph | compare → |
| 265/40R20 | 28.35" | +0.07% | +30 mm | 60.0 mph | compare → |
| 305/40R20 | 29.61" | +4.52% | +70 mm | 62.7 mph | compare → |
| 315/30R20 | 27.44" | -3.13% | +80 mm | 58.1 mph | compare → |
| 235/40R20 | 27.40" | -3.27% | 0 mm | 58.0 mph | calculate → |
| 335/30R20 | 27.91" | -1.46% | +100 mm | 59.1 mph | calculate → |
| 325/30R20 | 27.68" | -2.29% | +90 mm | 58.6 mph | calculate → |
| 345/30R20 | 28.15" | -0.63% | +110 mm | 59.6 mph | calculate → |
| 215/45R20 | 27.62" | -2.50% | -20 mm | 58.5 mph | calculate → |
| 325/35R20 | 28.96" | +2.22% | +90 mm | 61.3 mph | calculate → |
| 195/50R20 | 27.68" | -2.29% | -40 mm | 58.6 mph | calculate → |
| 225/40R20 | 27.09" | -4.38% | -10 mm | 57.4 mph | calculate → |
| 29x15.00R20 | 29.00" | +2.38% | +146 mm | 61.4 mph | calculate → |
| 29x18.00R20 | 29.00" | +2.38% | +222 mm | 61.4 mph | calculate → |
| 175/55R20 | 27.58" | -2.64% | -60 mm | 58.4 mph | calculate → |
| 145/65R20 | 27.42" | -3.20% | -90 mm | 58.1 mph | calculate → |
| 155/60R20 | 27.32" | -3.54% | -80 mm | 57.9 mph | calculate → |
| 195/55R20 | 28.44" | +0.42% | -40 mm | 60.3 mph | calculate → |
| 225/45R20 | 27.97" | -1.25% | -10 mm | 59.2 mph | calculate → |
| 155/65R20 | 27.93" | -1.39% | -80 mm | 59.2 mph | calculate → |
| 165/60R20 | 27.80" | -1.88% | -70 mm | 58.9 mph | calculate → |
| 175/70R20 | 29.65" | +4.66% | -60 mm | 62.8 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 | |
|---|---|---|---|---|---|
| 235/50R19 common | 28.25" | -0.26% | 0 mm | 59.8 mph | compare → |
| 275/35R21 common | 28.58" | +0.89% | +40 mm | 60.5 mph | compare → |
| 265/35R21 | 28.30" | -0.08% | +30 mm | 59.9 mph | compare → |
| 315/30R21 | 28.44" | +0.40% | +80 mm | 60.2 mph | compare → |
| 305/30R21 | 28.20" | -0.43% | +70 mm | 59.7 mph | compare → |
| 295/40R19 | 28.29" | -0.13% | +60 mm | 59.9 mph | compare → |
| 265/45R19 | 28.39" | +0.22% | +30 mm | 60.1 mph | calculate → |
| 345/35R19 | 28.51" | +0.64% | +110 mm | 60.4 mph | calculate → |
| 145/80R19 | 28.13" | -0.68% | -90 mm | 59.6 mph | calculate → |
Try another size against 235/45R20
Questions
What size is 235/45R20 in inches?
235/45R20 is about 28.3" tall and 9.3" wide on a 20-inch rim — roughly a 28.5x9.50R20 in inch sizing.
What does 235/45R20 mean?
235 mm section width, sidewall 45% of the width (4.16"), radial construction, 20-inch rim.
What tire sizes are equivalent to 235/45R20?
On the same 20" rim, within 3% of the diameter: 265/40R20 (+0.07%), 305/35R20 (+0.28%), 195/55R20 (+0.42%), 345/30R20 (-0.63%), 295/35R20 (-0.69%), 255/40R20 (-1.04%).
How many revolutions per mile does a 235/45R20 tire make?
About 712 revolutions per mile (circumference 89.0").
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.