245/45R20 tire size
A 245/45R20 tire is 28.7 inches tall and 9.6 inches wide. Here are its full dimensions, what the numbers mean, and the sizes you can swap it for.
- Overall diameter
- 28.68″ (729 mm)
- Section width
- 9.65″ (245 mm)
- Sidewall height
- 4.34″ (110 mm)
- Wheel diameter
- 20″
- Circumference
- 90.1″
- Revolutions per mile
- 703
What 245/45R20 means
- 245: the tire is 245 mm (9.6 in) wide from sidewall to sidewall.
- 45: the sidewall is 45% of the width, 110.3 mm (4.34 in) tall.
- R: radial construction, used by almost every modern tire.
- 20: it fits a 20-inch wheel.
Overall diameter = 20 + 2 × 4.34 = 28.68 inches.
Sizes equivalent to 245/45R20
These sizes are within 3% of the overall diameter, the usual limit for swapping without speedometer problems.
| Size | Diameter | Difference | Speedometer at 60 mph |
|---|---|---|---|
| 245/40R21 | 28.7″ | +0.1% | 60.1 mph actual |
| 245/35R22 | 28.8″ | +0.2% | 60.1 mph actual |
| 225/50R20 | 28.9″ | +0.6% | 60.4 mph actual |
| 235/35R22 | 28.5″ | -0.7% | 59.6 mph actual |
| 235/40R21 | 28.4″ | -1.0% | 59.4 mph actual |
| 225/45R21 | 29.0″ | +1.0% | 60.6 mph actual |
| 265/40R20 | 28.3″ | -1.2% | 59.3 mph actual |
| 255/35R22 | 29.0″ | +1.2% | 60.7 mph actual |
| 255/40R21 | 29.0″ | +1.2% | 60.7 mph actual |
| 255/45R20 | 29.0″ | +1.2% | 60.7 mph actual |
Going a size taller? 255/45R20 is 29.0″ tall, 1.2% more than 245/45R20. Compare any two sizes in the tire size calculator.
See every common size side by side in the tire size chart.
Questions
What is 245/45R20 in inches?
A 245/45R20 tire is about 28.7 inches tall (729 mm) and 9.6 inches wide, on a 20-inch wheel. In flotation sizing that's roughly 28.7x9.6R20.
How tall is a 245/45R20 tire?
The overall diameter is 28.68 inches: the 20-inch wheel plus two 4.34-inch sidewalls. Actual tires vary by a few tenths of an inch between brands and models.
Can I put 255/45R20 instead of 245/45R20?
255/45R20 is 0.35 inches taller (1.2%) and 10 mm wider. That's within the usual 3% limit, but check that your wheel width is approved for it and that it clears the suspension.
How many revolutions per mile does a 245/45R20 make?
About 703 revolutions per mile, from a circumference of 90.1 inches.
