33×12.50R18 in inches

A 33×12.50R18 tire is 33.0″ tall and 12.5″ wide, and fits a 18″ wheel.

Diameter33.00″

Width12.50″

Sidewall7.50″

Drawn to scale. Nominal dimensions calculated from the size code.

Manufacturer data

How tall 33×12.50R18 tires really are

Heights published by BFGoodrich, General, Mickey Thompson and Toyo for all 11 tires in this size. Their published revolutions per mile work out to 31.5–32.0″ under load (below).

Real 33×12.50R18 tires measure 32.50–33.00″, against 33.00″ from the size code. Most run shorter than the size code (9 of 11).

General Grabber X3 · 233.00″ +0.00″
Toyo Open Country M/T · 232.76–32.95″ −0.24″
Toyo Open Country R/T Pro32.80″ −0.20″
Mickey Thompson Baja Boss M/T32.70″ −0.30″
Mickey Thompson Baja Boss A/T32.60″ −0.40″
Toyo Open Country A/T III32.52″ −0.48″
Toyo Open Country R/T Trail32.52″ −0.48″
BFGoodrich All-Terrain T/A KO332.50″ −0.50″
BFGoodrich Mud-Terrain T/A KM332.50″ −0.50″

Each bar runs from the size code's 33.00″ (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 load31.5–32.0″

Published revs per mile (630–640) mean the tire rolls like a 31.5–32.0″ tire on the vehicle. Use this for speedometer calibration.

Weight spread63.0–73.9 lb

The lightest (BFGoodrich All-Terrain T/A KO3, LT E) is 10.9 lb lighter per corner than the heaviest (Toyo Open Country M/T, LT F).

11 tires in 33×12.50R18

Sort by the spec you care about.

	Load					Revs/mi	Source
BFGoodrich All-Terrain T/A KO3All-terrain	LT E · 118S	32.50	63.0	15.0	2,910	640	Spec page
Toyo Open Country R/T TrailRugged-terrain	LT F · 122Q	32.52	63.1	16.9	3,305	639	Spec page
Toyo Open Country A/T IIIAll-terrain	LT F · 122Q	32.52	64.8	16.9	3,305	639	Spec page
Mickey Thompson Baja Boss A/TAll-terrain	LT E · 118Q	32.60	67.0	18.5	2,910	–	Spec page
Mickey Thompson Baja Boss M/TMud-terrain	LT E · 118Q	32.70	67.0	21.0	2,910	–	Spec page
Toyo Open Country R/T ProRugged-terrain	LT F · 122Q	32.80	67.7	19.9	3,305	634	Spec page
BFGoodrich Mud-Terrain T/A KM3Mud-terrain	LT E · 118Q	32.50	68.1	18.0	2,910	640	Spec page
General Grabber X3Mud-terrain	LT E · 118Q	33.00	69.6	21.0	2,910	630	Spec page
General Grabber X3Mud-terrain	LT E · 118Q	33.00	69.7	21.0	2,910	630	Spec page
Toyo Open Country M/TMud-terrain	LT E · 118Q	32.95	73.5	21.0	2,910	630	Spec page
Toyo Open Country M/TMud-terrain	LT F · 122Q	32.76	73.9	21.0	3,305	634	Spec page

Is a 33×12.50R18 really 33 inches tall?

32.7″

Mostly. The name says 33″, and the 11 tires here publish 32.50–33.00″.

All 33-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 33×12.50R18	Difference
305/60R18	32.41	-0.59″	-1.8%
245/75R18	32.47	-0.53″	-1.6%
285/65R18	32.59	-0.41″	-1.3%
265/70R18	32.61	-0.39″	-1.2%
235/80R18	32.80	-0.20″	-0.6%
33×12.50R17	33.00	0.00″	0.0%
275/70R18	33.16	+0.16″	+0.5%
325/60R18	33.35	+0.35″	+1.1%
305/65R18	33.61	+0.61″	+1.8%
285/70R18	33.71	+0.71″	+2.1%

How to read 33×12.50R18

How to read any tire size

How 33X12.50R18LT 118Q is printed on the sidewall. It's the most common code among the 11 tires here (6 of them); tires in this size come in other load and speed ratings too.

133Overall diameter

33 inches tall, measured on the approved wheel. Flotation sizes give every number in inches.

212.50Section width

12.50 inches across the widest point, or 318 mm.

3RConstruction

Radial construction.

418Wheel diameter

Mounts on a 18-inch wheel. Approved wheel widths run 8.5″ to 11.0″.

5LTLight truck

Marks a light truck (LT) tire.

6118Load index

Each tire carries up to 2,910 lb (1,320 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 2,910 lb each, as published.

Specification	Inches	Metric
Overall diameter	33.00	838 mm
Section width	12.50	318 mm
Sidewall height	7.50	190.5 mm
Circumference	103.7	2,633 mm
Revolutions per mile (calculated, unloaded)	611.2	380 per km
Revolutions per mile (published by manufacturers)	630–640	391–398 per km
Approved wheel width	8.5–11.0	216–279 mm

Speedometer error after switching to 33×12.50R18

Your actual speed– mph

Questions about 33×12.50R18

What is 33×12.50R18 in inches?

33.00 inches tall, 12.50 inches wide, on a 18-inch wheel. Manufacturers publish 32.50–33.00 inches for the 11 tires listed here.

How much does a 33×12.50R18 tire weigh?

Between 63.0 lb and 73.9 lb for the 11 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 F).

What wheel width do I need for 33×12.50R18?

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

How many revolutions per mile does a 33×12.50R18 make?

Published figures run 630–640 revolutions per mile. The calculated figure is 611.2, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 33×12.50R18 than 235/80R18?

0.20 inches taller on paper (33.00″ vs 32.80″), which raises the axle about 0.10″. Your speedometer will read about 0.6% slow.