305/40R20 tire size
305/40R20 in inches: 29.61" overall diameter — 12.01" wide, 4.80" sidewall.
Overall diameter 29.61 in 752 mm
Section width 12.01 in 305 mm
Sidewall height 4.80 in 122 mm
Revs / mile 681 speedo calibration
Full dimensions
| Measurement | Metric | Imperial |
|---|---|---|
| Overall diameter | 752 mm | 29.61 in |
| Section width | 305 mm | 12.01 in |
| Sidewall height | 122 mm | 4.80 in |
| Rim diameter | 508 mm | 20 in |
| Circumference | 2362.5 mm | 93.01 in |
| Revolutions per mile | 681.2 | |
| Aspect ratio | 40% | |
Compare 305/40R20 to similar sizes
Frequently asked questions
What is the overall diameter of a 305/40R20 tire?
A 305/40R20 tire has an overall diameter of 29.61 inches (752 mm).
How tall is a 305/40R20 tire?
The sidewall height is 122 mm (4.80 inches), and the overall diameter from the ground to the top of the tire is 29.61 inches.
How many revolutions per mile does a 305/40R20 tire make?
A 305/40R20 tire makes approximately 681 revolutions per mile. Your speedometer is calibrated to this number.
What rim size does a 305/40R20 tire fit?
A 305/40R20 tire is designed for a 20-inch rim (508 mm).
All dimensions calculated using standard ETRTO formulas. Always confirm fitment with your vehicle's door-placard and a qualified tire professional before purchasing.