tiresizeinches.com

Metric tire size · 20 in wheel

305/55R20 tire size in inches and millimeters

mm, 115–395
% of width
inches

Reading 305/55R20. Change any field and the gauge follows.

Overall diameter

33.21in

A 305/55R20 tire stands 33.21 in (843.5 mm) tall, which makes it a 33-inch tire, 0.21 in over.

Section width
12.01 in305 mm
Sidewall
6.60 in167.8 mm
Wheel
20 in508.0 mm
305/55R20 drawn to scaleA 305/55R20 tire drawn to scale, seen from the side and head-on at one scale. Four dimension lines label the overall diameter 33.21 in, the wheel diameter 20 in, the sidewall height 6.60 in and the section width 12.01 in. Every one of those values is stated in text on this page.33.21 in20 in wheel6.60 in12.01 in
Drawn to scale. Hover or focus a row in the equivalents table to lay that size over this one.

Full specification

305/55R20 — one measurement per row, in both unit systems
Dimension Inchesin Millimetersmm
Overall diameter33.21843.5
Section width12.01305.0
Sidewall height6.60167.8
Wheel diameter20.00508.0
Circumference104.332,649.9
305/55R20 — the quantities that are not one measurement in two units
QuantityValueUnit
Revolutions607.3per mile
Revolutions377.4per kilometer
Aspect ratio55% of section width
ConstructionRradial

Sizes that will do the same job

Where every equivalent size falls inside the tolerance bandA horizontal scale running from three percent under to three percent over the 305/55R20 overall diameter of 33.21 in. Each of the 10 sizes in the table is drawn as a tick at its own difference; the pointer marks 275/60R20 at −0.65%. Every plotted value is a row of the table below.−3−2−10123SHORTERTALLER275/60R20 · −0.65%
The scale is percent difference in overall diameter against 33.21 in. Every mark is a row of the table below, at its own distance from it.

10 sizes in this table are within ±3% of 33.21 in. A positive difference is taller than 305/55R20; every sign is printed as well as colored.

The most searched equivalents of 305/55R20, 10 listed, sorted by how far each is from 33.21 in. Open a row for its section width and speed.
Size Overall diameterin Difference vs 305/55R20% of diameter, then inches Actual speedmph at an indicated 60
32.99 −0.65% −0.22 in 59.6
33.46 +0.77% +0.26 in 60.5
33.56 +1.07% +0.35 in 60.6
32.80 −1.24% −0.41 in 59.3
33.64 +1.30% +0.43 in 60.8
32.78 −1.30% −0.43 in 59.2
32.52 −2.07% −0.69 in 58.8
33.94 +2.19% +0.73 in 61.3
34.07 +2.61% +0.87 in 61.6
32.34 −2.61% −0.87 in 58.4

The next sizes up and down

One width step and one profile step either side of 305/55R20, on the same wheel.
Size Overall diameterdifference % and inches Section widthvs 305/55R20, then mph at an indicated 60
narrower295/55R20 32.78−1.30% −0.43 in −0.39 in59.2 mph actual
wider315/55R20 33.64+1.30% +0.43 in +0.39 in60.8 mph actual
lower profile305/50R20 32.01−3.62% −1.20 in 0.00 in57.8 mph actual
taller profile305/60R20 34.41+3.62% +1.20 in 0.00 in62.2 mph actual