tireheight.com

305/50R20 in inches

A 305/50R20 tire is 32.0″ tall and 12.0″ wide, and fits a 20″ wheel. In inches it is written 32.0×12.0R20.

Diameter32.01″
Width12.01″
Sidewall6.00″
305/50R20 drawn to scale: 32.01 inch diameter, 6.00 inch sidewall, 20 inch wheel, 12.01 inch tread width20″ wheel6.00″32.01″ overall12.01″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 305/50R20 tires really are

Heights published by BFGoodrich, General, Michelin, Mickey Thompson and Toyo for all 8 tires in this size. Their published revolutions per mile work out to 31.1″ under load (below).

Real 305/50R20 tires measure 32.00–32.20″, against 32.01″ from the size code. They run both taller and shorter than the size code.

  1. Mickey Thompson Baja Boss A/T32.20″ +0.19″
  2. BFGoodrich All-Terrain T/A KO332.10″ +0.09″
  3. Toyo Open Country R/T Trail32.05″ +0.04″
  4. Toyo Open Country A/T III32.05″ +0.04″
  5. Toyo Proxes ST III32.05″ +0.04″
  6. General G-MAX AS0732.00″ −0.01″
  7. General Grabber A/TX32.00″ −0.01″
  8. Michelin Defender LTX M/S 232.00″ −0.01″
Each bar runs from the size code's 32.01″ (the orange line) to the model's published height. The track spans 1.0″. Where a model comes in several load ranges, the darker part shows its range of heights; the number after the name is how many versions it comes in.
Height under load31.1″

Published revs per mile (648–649) mean the tire rolls like a 31.1″ tire on the vehicle. Use this for speedometer calibration.

Weight spread42.3–62.0 lb

The lightest (General G-MAX AS07, XL) is 19.7 lb lighter per corner than the heaviest (BFGoodrich All-Terrain T/A KO3, LT E).

8 tires in 305/50R20

Sort by the spec you care about.

LoadRevs/miSource
General G-MAX AS07PerformanceXL · 120V32.0042.311.03,086649Spec page
Michelin Defender LTX M/S 2All-seasonXL · 120H32.0043.211.03,086649Spec page
Toyo Proxes ST IIIPerformanceXL · 120V32.0543.910.33,086648Spec page
Toyo Open Country A/T IIIAll-terrainXL · 120T32.0546.813.93,086648Spec page
Toyo Open Country R/T TrailRugged-terrainXL · 120Q32.0548.813.93,086648Spec page
General Grabber A/TXAll-terrainXL · 120T32.0048.914.03,086649Spec page
Mickey Thompson Baja Boss A/TAll-terrainXL · 120T32.2051.016.03,086–Spec page
BFGoodrich All-Terrain T/A KO3All-terrainLT E · 117S32.1062.015.02,835649Spec page

Is 305/50R20 a 32-inch tire?

≈32″

Yes. The size code works out to 32.01″, and the 8 tires here publish 32.00–32.20″, so people call it a 32.

All 32-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 305/50R20Difference
235/60R2031.10-0.91″-2.8%
285/50R2031.22-0.79″-2.5%
265/55R2031.48-0.53″-1.7%
245/60R2031.57-0.43″-1.4%
275/55R2031.91-0.10″-0.3%
255/60R2032.05+0.04″+0.1%
255/65R1932.05+0.04″+0.1%
285/55R2032.34+0.33″+1.0%
265/60R2032.52+0.51″+1.6%
295/55R2032.78+0.77″+2.4%

How to read 305/50R20

How to read any tire size

305/50R20 120T as printed on the tire sidewall, with each part numbered305/50R20 120T123456
How 305/50R20 120T is printed on the sidewall. It's the most common code among the 8 tires here (3 of them); tires in this size come in other load and speed ratings too.
1305Section width

305 mm across the widest point, or 12.01 inches. Every 305 size

250Aspect ratio

A percentage, not a measurement: the sidewall is 50% as tall as the tire is wide, which is 152.5 mm or 6.00 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.5″ to 11.0″.

5120Load index

Each tire carries up to 3,085 lb (1,400 kg) at its maximum pressure.

6TSpeed rating

Rated for up to 118 mph sustained.

XLExtra load

Printed after the size.

SpecificationInchesMetric
Overall diameter32.01813 mm
Section width12.01305 mm
Sidewall height6.00152.5 mm
Circumference100.62,554 mm
Revolutions per mile (calculated, unloaded)630.1392 per km
Revolutions per mile (published by manufacturers)648–649403 per km
Approved wheel width8.5–11.0216–279 mm

Speedometer error after switching to 305/50R20

Your actual speed– mph

Questions about 305/50R20

What is 305/50R20 in inches?

32.01 inches tall, 12.01 inches wide, on a 20-inch wheel. Written in inches, that is roughly 32.0×12.0R20.

How much does a 305/50R20 tire weigh?

Between 42.3 lb and 62.0 lb for the 8 tires listed here. The lightest is the General G-MAX AS07 (XL); the heaviest is the BFGoodrich All-Terrain T/A KO3 (LT E).

What wheel width do I need for 305/50R20?

Manufacturers approve 8.5–11.0″ wide wheels for this size.

How many revolutions per mile does a 305/50R20 make?

Published figures run 648–649 revolutions per mile. The calculated figure is 630.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.

What is the difference between P305/50R20 and LT305/50R20?

Passenger tires (7 here) are built for passenger loads, with max loads of 3086 lb. Light-truck tires (1 here) come in heavier load ranges with max loads of 2835 lb, and are usually heavier with deeper tread.

How much taller is 305/50R20 than 275/55R20?

0.10 inches taller on paper (32.01″ vs 31.91″), which raises the axle about 0.05″. Your speedometer will read about 0.3% slow.