245/45R20 tire size
245/45R20 is a metric size: 28.7" tall, 9.6" wide, on a 20" rim — about a 28.5x9.50R20. The sidewall is 4.3" and the tire turns 703 times per mile.
245/45R20 specs
| Overall diameter (height) | 28.68" · 729 mm |
|---|---|
| Section width | 9.65" · 245 mm |
| Sidewall height | 4.34" · 110 mm (45% of width) |
| Rim diameter | 20" |
| Circumference | 90.10" · 2.289 m |
| Revolutions per mile | 703 (437 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 | |
|---|---|---|---|---|---|
| 255/45R20 common | 29.04" | +1.24% | +10 mm | 60.7 mph | compare → |
| 275/40R20 common | 28.66" | -0.07% | +30 mm | 60.0 mph | compare → |
| 255/50R20 common | 30.04" | +4.74% | +10 mm | 62.8 mph | compare → |
| 245/40R20 common | 27.72" | -3.36% | 0 mm | 58.0 mph | compare → |
| 245/50R20 common | 29.65" | +3.36% | 0 mm | 62.0 mph | compare → |
| 275/45R20 common | 29.74" | +3.71% | +30 mm | 62.2 mph | compare → |
| 255/40R20 common | 28.03" | -2.26% | +10 mm | 58.6 mph | compare → |
| 275/35R20 common | 27.58" | -3.84% | +30 mm | 57.7 mph | compare → |
| 265/45R20 common | 29.39" | +2.47% | +20 mm | 61.5 mph | compare → |
| 285/35R20 common | 27.85" | -2.88% | +40 mm | 58.3 mph | compare → |
| 315/35R20 common | 28.68" | 0.00% | +70 mm | 60.0 mph | compare → |
| 265/35R20 common | 27.30" | -4.80% | +20 mm | 57.1 mph | compare → |
| 295/40R20 | 29.29" | +2.13% | +50 mm | 61.3 mph | compare → |
| 295/35R20 | 28.13" | -1.92% | +50 mm | 58.8 mph | compare → |
| 305/35R20 | 28.41" | -0.96% | +60 mm | 59.4 mph | compare → |
| 285/40R20 | 28.98" | +1.03% | +40 mm | 60.6 mph | compare → |
| 235/50R20 | 29.25" | +1.99% | -10 mm | 61.2 mph | compare → |
| 235/45R20 | 28.33" | -1.24% | -10 mm | 59.3 mph | compare → |
| 285/45R20 | 30.10" | +4.94% | +40 mm | 63.0 mph | compare → |
| 265/40R20 | 28.35" | -1.17% | +20 mm | 59.3 mph | compare → |
| 305/40R20 | 29.61" | +3.23% | +60 mm | 61.9 mph | compare → |
| 315/30R20 | 27.44" | -4.32% | +70 mm | 57.4 mph | compare → |
| 235/40R20 | 27.40" | -4.46% | -10 mm | 57.3 mph | calculate → |
| 335/30R20 | 27.91" | -2.68% | +90 mm | 58.4 mph | calculate → |
| 325/30R20 | 27.68" | -3.50% | +80 mm | 57.9 mph | calculate → |
| 345/30R20 | 28.15" | -1.85% | +100 mm | 58.9 mph | calculate → |
| 215/45R20 | 27.62" | -3.71% | -30 mm | 57.8 mph | calculate → |
| 325/35R20 | 28.96" | +0.96% | +80 mm | 60.6 mph | calculate → |
| 195/50R20 | 27.68" | -3.50% | -50 mm | 57.9 mph | calculate → |
| 29x15.00R20 | 29.00" | +1.11% | +136 mm | 60.7 mph | calculate → |
| 29x18.00R20 | 29.00" | +1.11% | +212 mm | 60.7 mph | calculate → |
| 175/55R20 | 27.58" | -3.84% | -70 mm | 57.7 mph | calculate → |
| 145/65R20 | 27.42" | -4.39% | -100 mm | 57.4 mph | calculate → |
| 155/60R20 | 27.32" | -4.74% | -90 mm | 57.2 mph | calculate → |
| 195/55R20 | 28.44" | -0.82% | -50 mm | 59.5 mph | calculate → |
| 225/45R20 | 27.97" | -2.47% | -20 mm | 58.5 mph | calculate → |
| 155/65R20 | 27.93" | -2.61% | -90 mm | 58.4 mph | calculate → |
| 165/60R20 | 27.80" | -3.09% | -80 mm | 58.1 mph | calculate → |
| 175/70R20 | 29.65" | +3.36% | -70 mm | 62.0 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 | |
|---|---|---|---|---|---|
| 225/55R19 common | 28.74" | +0.22% | -20 mm | 60.1 mph | compare → |
| 245/50R19 common | 28.65" | -0.12% | 0 mm | 59.9 mph | compare → |
| 275/35R21 common | 28.58" | -0.36% | +30 mm | 59.8 mph | compare → |
| 325/30R21 | 28.68" | -0.01% | +80 mm | 60.0 mph | compare → |
| 275/45R19 | 28.74" | +0.22% | +30 mm | 60.1 mph | compare → |
| 285/35R21 | 28.85" | +0.60% | +40 mm | 60.4 mph | compare → |
| 315/30R21 | 28.44" | -0.84% | +70 mm | 59.5 mph | compare → |
| 245/40R21 | 28.72" | +0.12% | 0 mm | 60.1 mph | compare → |
| 335/30R21 | 28.91" | +0.81% | +90 mm | 60.5 mph | calculate → |
| 345/35R19 | 28.51" | -0.60% | +100 mm | 59.6 mph | calculate → |
| 155/80R19 | 28.76" | +0.29% | -90 mm | 60.2 mph | calculate → |
| 315/40R19 | 28.92" | +0.84% | +70 mm | 60.5 mph | calculate → |
Try another size against 245/45R20
Questions
What size is 245/45R20 in inches?
245/45R20 is about 28.7" tall and 9.6" wide on a 20-inch rim — roughly a 28.5x9.50R20 in inch sizing.
What does 245/45R20 mean?
245 mm section width, sidewall 45% of the width (4.34"), radial construction, 20-inch rim.
What tire sizes are equivalent to 245/45R20?
On the same 20" rim, within 3% of the diameter: 315/35R20 (0.00%), 275/40R20 (-0.07%), 195/55R20 (-0.82%), 305/35R20 (-0.96%), 325/35R20 (+0.96%), 285/40R20 (+1.03%).
How many revolutions per mile does a 245/45R20 tire make?
About 703 revolutions per mile (circumference 90.1").
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.