tireheight.com

285/55R20 in inches

A 285/55R20 tire is 32.3″ tall and 11.2″ wide, and fits a 20″ wheel. In inches it is written 32.3×11.2R20.

Diameter32.34″
Width11.22″
Sidewall6.17″
285/55R20 drawn to scale: 32.34 inch diameter, 6.17 inch sidewall, 20 inch wheel, 11.22 inch tread width20″ wheel6.17″32.34″ overall11.22″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 285/55R20 tires really are

Heights published by BFGoodrich, General, Michelin, Mickey Thompson and Toyo for all 12 tires in this size. Their published revolutions per mile work out to 31.4–31.7″ under load (below).

Real 285/55R20 tires measure 32.30–32.70″, against 32.34″ from the size code. They run both taller and shorter than the size code.

  1. Mickey Thompson Baja Boss A/T32.70″ +0.36″
  2. Mickey Thompson Baja Boss M/T32.60″ +0.26″
  3. Mickey Thompson Baja Legend EXP32.60″ +0.26″
  4. Toyo Open Country C/T32.60″ +0.26″
  5. BFGoodrich All-Terrain T/A KO332.40″ +0.06″
  6. Michelin Defender LTX M/S 232.40″ +0.06″
  7. Toyo Open Country R/T Pro32.40″ +0.06″
  8. Toyo Open Country A/T III · 232.36″ +0.02″
  9. Toyo Open Country R/T Trail · 232.36″ +0.02″
  10. General Grabber A/TX32.30″ −0.04″
Each bar runs from the size code's 32.34″ (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 load31.4–31.7″

Published revs per mile (637–643) mean the tire rolls like a 31.4–31.7″ tire on the vehicle. Use this for speedometer calibration.

Weight spread41.0–65.0 lb

The lightest (Michelin Defender LTX M/S 2, XL) is 24.0 lb lighter per corner than the heaviest (Toyo Open Country C/T, LT E).

12 tires in 285/55R20

Sort by the spec you care about.

LoadRevs/miSource
Michelin Defender LTX M/S 2All-seasonXL · 116T32.4041.012.52,756643Spec page
Toyo Open Country A/T IIIAll-terrainSL · 114T32.3644.613.62,601642Spec page
Toyo Open Country R/T TrailRugged-terrainXL · 116T32.3645.913.62,756642Spec page
Toyo Open Country A/T IIIAll-terrainLT E · 122/119T32.3654.216.53,305642Spec page
General Grabber A/TXAll-terrainLT D · 117T32.3056.315.02,833642Spec page
Toyo Open Country R/T TrailRugged-terrainLT E · 122/119Q32.3657.616.53,305642Spec page
BFGoodrich All-Terrain T/A KO3All-terrainLT D · 117S32.4058.115.02,835643Spec page
Mickey Thompson Baja Legend EXPAll-terrainLT E · 122Q32.6059.018.53,305–Spec page
Toyo Open Country R/T ProRugged-terrainLT E · 122/119Q32.4061.317.13,305642Spec page
Mickey Thompson Baja Boss A/TAll-terrainLT E · 122Q32.7062.018.53,305–Spec page
Mickey Thompson Baja Boss M/TMud-terrainLT E · 122Q32.6063.018.53,305–Spec page
Toyo Open Country C/TCommercialLT E · 122/119Q32.6065.018.43,305637Spec page

Is 285/55R20 a 32-inch tire?

≈32″

Close. The size code works out to 32.34″, and the 12 tires here publish 32.30–32.70″, 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 285/55R20Difference
245/60R2031.57-0.77″-2.4%
275/55R2031.91-0.43″-1.3%
305/50R2032.01-0.33″-1.0%
255/60R2032.05-0.30″-0.9%
265/60R2032.52+0.18″+0.5%
295/55R2032.78+0.43″+1.3%
275/60R2032.99+0.65″+2.0%
33×11.50R2033.00+0.66″+2.0%
33×12.50R2033.00+0.66″+2.0%
33×13.50R2033.00+0.66″+2.0%

How to read 285/55R20

How to read any tire size

LT285/55R20 122Q as printed on the tire sidewall, with each part numberedLT285/55R20 122Q1234567
How LT285/55R20 122Q is printed on the sidewall. It's the most common code among the 12 tires here (3 of them); tires in this size come in other load and speed ratings too.
1LTLight truck

Marks a light truck (LT) tire.

2285Section width

285 mm across the widest point, or 11.22 inches. Every 285 size

355Aspect ratio

A percentage, not a measurement: the sidewall is 55% as tall as the tire is wide, which is 156.8 mm or 6.17 inches.

4RConstruction

Radial construction.

520Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.0″ to 10.0″.

6122Load index

Each tire carries up to 3,305 lb (1,500 kg) at its maximum pressure.

7QSpeed rating

Rated for up to 99 mph sustained.

ELoad range

Printed separately as "LOAD RANGE E": a 10-ply rating, inflated up to 80 psi (standard load-range table). The load range E tires here carry up to 3,305 lb each, as published.

SpecificationInchesMetric
Overall diameter32.34822 mm
Section width11.22285 mm
Sidewall height6.17156.8 mm
Circumference101.62,581 mm
Revolutions per mile (calculated, unloaded)623.6387 per km
Revolutions per mile (published by manufacturers)637–643396–400 per km
Approved wheel width8.0–10.0203–254 mm

Speedometer error after switching to 285/55R20

Your actual speed– mph

Questions about 285/55R20

What is 285/55R20 in inches?

32.34 inches tall, 11.22 inches wide, on a 20-inch wheel. Written in inches, that is roughly 32.3×11.2R20.

How much does a 285/55R20 tire weigh?

Between 41.0 lb and 65.0 lb for the 12 tires listed here. The lightest is the Michelin Defender LTX M/S 2 (XL); the heaviest is the Toyo Open Country C/T (LT E).

What wheel width do I need for 285/55R20?

Manufacturers approve 8.0–10.0″ wide wheels for this size.

How many revolutions per mile does a 285/55R20 make?

Published figures run 637–643 revolutions per mile. The calculated figure is 623.6, but manufacturers measure the tire under load, where it rolls on a smaller radius.

What is the difference between P285/55R20 and LT285/55R20?

Passenger tires (3 here) are built for passenger loads, with max loads of 2601–2756 lb. Light-truck tires (9 here) come in heavier load ranges with max loads of 2833–3305 lb, and are usually heavier with deeper tread.

How much taller is 285/55R20 than 255/60R20?

0.30 inches taller on paper (32.34″ vs 32.05″), which raises the axle about 0.15″. Your speedometer will read about 0.9% slow.