275/45R20 tire size
275/45R20 is a metric size: 29.7" tall, 10.8" wide, on a 20" rim — about a 29.5x11.00R20. The sidewall is 4.9" and the tire turns 678 times per mile.
275/45R20 specs
| Overall diameter (height) | 29.74" · 756 mm |
|---|---|
| Section width | 10.83" · 275 mm |
| Sidewall height | 4.87" · 124 mm (45% of width) |
| Rim diameter | 20" |
| Circumference | 93.44" · 2.373 m |
| Revolutions per mile | 678 (421 per km) |
| Inch (flotation) equivalent | 29.5x11.00R20 |
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" | -3.57% | -30 mm | 57.9 mph | compare → |
| 255/45R20 common | 29.04" | -2.38% | -20 mm | 58.6 mph | compare → |
| 255/50R20 common | 30.04" | +0.99% | -20 mm | 60.6 mph | compare → |
| 275/40R20 common | 28.66" | -3.64% | 0 mm | 57.8 mph | compare → |
| 265/50R20 common | 30.43" | +2.32% | -10 mm | 61.4 mph | compare → |
| 245/50R20 common | 29.65" | -0.33% | -30 mm | 59.8 mph | compare → |
| 255/55R20 common | 31.04" | +4.37% | -20 mm | 62.6 mph | compare → |
| 235/55R20 common | 30.18" | +1.46% | -40 mm | 60.9 mph | compare → |
| 265/45R20 common | 29.39" | -1.19% | -10 mm | 59.3 mph | compare → |
| 315/35R20 common | 28.68" | -3.57% | +40 mm | 57.9 mph | compare → |
| 275/50R20 common | 30.83" | +3.64% | 0 mm | 62.2 mph | compare → |
| 295/40R20 | 29.29" | -1.52% | +20 mm | 59.1 mph | compare → |
| 285/50R20 | 31.22" | +4.96% | +10 mm | 63.0 mph | compare → |
| 305/35R20 | 28.41" | -4.50% | +30 mm | 57.3 mph | compare → |
| 285/40R20 | 28.98" | -2.58% | +10 mm | 58.5 mph | compare → |
| 235/50R20 | 29.25" | -1.65% | -40 mm | 59.0 mph | compare → |
| 285/45R20 | 30.10" | +1.19% | +10 mm | 60.7 mph | compare → |
| 235/45R20 | 28.33" | -4.77% | -40 mm | 57.1 mph | compare → |
| 295/45R20 | 30.45" | +2.38% | +20 mm | 61.4 mph | compare → |
| 265/40R20 | 28.35" | -4.70% | -10 mm | 57.2 mph | compare → |
| 305/40R20 | 29.61" | -0.46% | +30 mm | 59.7 mph | compare → |
| 235/60R20 | 31.10" | +4.57% | -40 mm | 62.7 mph | calculate → |
| 325/35R20 | 28.96" | -2.65% | +50 mm | 58.4 mph | calculate → |
| 29x15.00R20 | 29.00" | -2.50% | +106 mm | 58.5 mph | calculate → |
| 29x18.00R20 | 29.00" | -2.50% | +182 mm | 58.5 mph | calculate → |
| 305/45R20 | 30.81" | +3.57% | +30 mm | 62.1 mph | calculate → |
| 31x18.00R20 | 31.00" | +4.22% | +182 mm | 62.5 mph | calculate → |
| 175/70R20 | 29.65" | -0.33% | -100 mm | 59.8 mph | calculate → |
| 195/55R20 | 28.44" | -4.37% | -80 mm | 57.4 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 | |
|---|---|---|---|---|---|
| 245/55R19 common | 29.61" | -0.45% | -30 mm | 59.7 mph | compare → |
| 285/40R21 | 29.98" | +0.78% | +10 mm | 60.5 mph | compare → |
| 275/40R21 | 29.66" | -0.28% | 0 mm | 59.8 mph | compare → |
| 315/35R21 | 29.68" | -0.21% | +40 mm | 59.9 mph | compare → |
| 255/45R21 | 30.04" | +0.98% | -20 mm | 60.6 mph | compare → |
| 245/45R21 | 29.68" | -0.21% | -30 mm | 59.9 mph | compare → |
| 275/50R19 | 29.83" | +0.28% | 0 mm | 60.2 mph | compare → |
| 295/45R19 | 29.45" | -0.98% | +20 mm | 59.4 mph | calculate → |
| 175/80R19 | 30.02" | +0.94% | -100 mm | 60.6 mph | calculate → |
Try another size against 275/45R20
Questions
What size is 275/45R20 in inches?
275/45R20 is about 29.7" tall and 10.8" wide on a 20-inch rim — roughly a 29.5x11.00R20 in inch sizing.
What does 275/45R20 mean?
275 mm section width, sidewall 45% of the width (4.87"), radial construction, 20-inch rim.
What tire sizes are equivalent to 275/45R20?
On the same 20" rim, within 3% of the diameter: 175/70R20 (-0.33%), 245/50R20 (-0.33%), 305/40R20 (-0.46%), 255/50R20 (+0.99%), 285/45R20 (+1.19%), 265/45R20 (-1.19%).
How many revolutions per mile does a 275/45R20 tire make?
About 678 revolutions per mile (circumference 93.4").
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.