tireheight.com

285/75R18 in inches

A 285/75R18 tire is 34.8″ tall and 11.2″ wide, and fits a 18″ wheel. In inches it is written 34.8×11.2R18.

Diameter34.83″
Width11.22″
Sidewall8.42″
285/75R18 drawn to scale: 34.83 inch diameter, 8.42 inch sidewall, 18 inch wheel, 11.22 inch tread width18″ wheel8.42″34.83″ overall11.22″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 285/75R18 tires really are

Heights published by BFGoodrich and Toyo for all 6 tires in this size. Their published revolutions per mile work out to 33.8–34.1″ under load (below).

Real 285/75R18 tires measure 34.80–35.06″, against 34.83″ from the size code. They run both taller and shorter than the size code.

  1. Toyo Open Country M/T35.06″ +0.23″
  2. Toyo Open Country A/T III34.84″ +0.01″
  3. Toyo Open Country R/T Trail34.84″ +0.01″
  4. BFGoodrich All-Terrain T/A KO334.80″ −0.03″
  5. BFGoodrich HD-Terrain T/A KT34.80″ −0.03″
  6. Toyo Open Country R/T Pro34.80″ −0.03″
Each bar runs from the size code's 34.83″ (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 load33.8–34.1″

Published revs per mile (591–597) mean the tire rolls like a 33.8–34.1″ tire on the vehicle. Use this for speedometer calibration.

Weight spread63.5–71.8 lb

The lightest (BFGoodrich All-Terrain T/A KO3, LT E) is 8.3 lb lighter per corner than the heaviest (Toyo Open Country M/T, LT E).

6 tires in 285/75R18

Sort by the spec you care about.

LoadRevs/miSource
BFGoodrich All-Terrain T/A KO3All-terrainLT E · 129S34.8063.516.04,080597Spec page
Toyo Open Country A/T IIIAll-terrainLT E · 129/126S34.8464.516.54,080596Spec page
Toyo Open Country R/T ProRugged-terrainLT E · 129/126Q34.8065.217.14,080596Spec page
BFGoodrich HD-Terrain T/A KTLT E · 129Q34.8066.018.04,080597Spec page
Toyo Open Country R/T TrailRugged-terrainLT E · 129/126R34.8466.516.54,080596Spec page
Toyo Open Country M/TMud-terrainLT E · 129P35.0671.819.14,080591Spec page

Is 285/75R18 a 35-inch tire?

≈35″

Yes. The size code works out to 34.83″, and the 6 tires here publish 34.80–35.06″, so people call it a 35.

All 35-inch tire sizes, on every wheel size.

A true 35×12.50R18 is 0.17″ taller on paper and 1.3″ wider.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 285/75R18Difference
285/70R1833.71-1.12″-3.2%
295/70R1834.26-0.57″-1.6%
295/75R1734.42-0.41″-1.2%
325/65R1834.63-0.20″-0.6%
305/70R1834.81-0.02″-0.1%
35×12.50R1835.00+0.17″+0.5%
35×10.50R1735.00+0.17″+0.5%
35×11.50R1735.00+0.17″+0.5%
35×12.50R1735.00+0.17″+0.5%
315/70R1835.36+0.53″+1.5%

How to read 285/75R18

How to read any tire size

LT285/75R18 129S as printed on the tire sidewall, with each part numberedLT285/75R18 129S1234567
How LT285/75R18 129S is printed on the sidewall. It's the most common code among the 6 tires here (1 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

375Aspect ratio

A percentage, not a measurement: the sidewall is 75% as tall as the tire is wide, which is 213.7 mm or 8.42 inches.

4RConstruction

Radial construction.

518Wheel diameter

Mounts on a 18-inch wheel. Approved wheel widths run 7.5″ to 9.5″.

6129Load index

Each tire carries up to 4,080 lb (1,850 kg) at its maximum pressure.

7SSpeed rating

Rated for up to 112 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 4,080 lb each, as published.

SpecificationInchesMetric
Overall diameter34.83885 mm
Section width11.22285 mm
Sidewall height8.42213.7 mm
Circumference109.42,779 mm
Revolutions per mile (calculated, unloaded)579.0360 per km
Revolutions per mile (published by manufacturers)591–597367–371 per km
Approved wheel width7.5–9.5191–241 mm

Speedometer error after switching to 285/75R18

Your actual speed– mph

Questions about 285/75R18

What is 285/75R18 in inches?

34.83 inches tall, 11.22 inches wide, on a 18-inch wheel. Written in inches, that is roughly 34.8×11.2R18.

How much does a 285/75R18 tire weigh?

Between 63.5 lb and 71.8 lb for the 6 tires listed here. The lightest is the BFGoodrich All-Terrain T/A KO3 (LT E); the heaviest is the Toyo Open Country M/T (LT E).

What wheel width do I need for 285/75R18?

Manufacturers approve 7.5–9.5″ wide wheels for this size.

How many revolutions per mile does a 285/75R18 make?

Published figures run 591–597 revolutions per mile. The calculated figure is 579.0, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 285/75R18 than 305/70R18?

0.02 inches taller on paper (34.83″ vs 34.81″), which raises the axle about 0.01″. Your speedometer will read about 0.1% slow.