255/30R20 Tire Size Specifications & Compatible Vehicles
Overall Diameter
661.0 mm
Section Width
255 mm
Sidewall Height
76.5 mm
Circumference
2076.6 mm
Revs/Mile
775
Rim Diameter
20"
Inch Equivalent
26x10R20
Rim Width (ETRTO)
7.5" – 10.0"
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 255/30R20 and may be used as replacements:
Understanding 255/30R20
The tire size 255/30R20 means the tire has a section width of 255mm, an aspect ratio of 30% (the sidewall height is 30% of the width), and fits a 20-inch rim.
Sidewall Height = 255 x 0.3 = 76.5 mm
Overall Diameter = (76.5 x 2) + (20 x 25.4) = 661.0 mm
Circumference = 661.0 x π = 2076.6 mm
Overall Diameter = (76.5 x 2) + (20 x 25.4) = 661.0 mm
Circumference = 661.0 x π = 2076.6 mm
Frequently Asked Questions
The 255/30R20 is a standard tire size. Check your vehicle door jamb sticker or owner manual to confirm compatibility.
A 255/30R20 tire has an overall diameter of 661.0mm (26.0 inches). The sidewall height is 76.5mm, and the total circumference is 2077mm.
For 255/30R20 tires, the ETRTO recommended rim width is 8.5". The acceptable range is 7.5" minimum to 10.0" 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 255/30R20 661.0mm diameter. Compatible alternatives include 255/35R19, 255/25R21, 255/40R18. Use our Tire Size Calculator to compare any two sizes.