305/55R20 Tire Size Specifications & Compatible Vehicles
Overall Diameter
843.5 mm
Section Width
305 mm
Sidewall Height
167.8 mm
Circumference
2649.9 mm
Revs/Mile
607
Rim Diameter
20"
Inch Equivalent
33.2x12R20
Rim Width (ETRTO)
9.5" – 12.0"
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 305/55R20 and may be used as replacements:
Popular Comparisons
See how 305/55R20 compares to other common tire sizes:
Understanding 305/55R20
The tire size 305/55R20 means the tire has a section width of 305mm, an aspect ratio of 55% (the sidewall height is 55% of the width), and fits a 20-inch rim.
Sidewall Height = 305 x 0.55 = 167.8 mm
Overall Diameter = (167.8 x 2) + (20 x 25.4) = 843.5 mm
Circumference = 843.5 x π = 2649.9 mm
Overall Diameter = (167.8 x 2) + (20 x 25.4) = 843.5 mm
Circumference = 843.5 x π = 2649.9 mm
Frequently Asked Questions
The 305/55R20 is a standard tire size. Check your vehicle door jamb sticker or owner manual to confirm compatibility.
A 305/55R20 tire has an overall diameter of 843.5mm (33.2 inches). The sidewall height is 167.8mm, and the total circumference is 2650mm.
For 305/55R20 tires, the ETRTO recommended rim width is 10.5". The acceptable range is 9.5" minimum to 12.0" maximum. Using a rim outside this range can cause improper bead seating and unsafe handling.
Yes, as long as the replacement tire overall diameter is within 3% of the 305/55R20 843.5mm diameter. Compatible alternatives include 285/50R22, 345/45R21, 335/50R20. Use our Tire Size Calculator to compare any two sizes.