42×13.50R20 in inches

A 42×13.50R20 tire is 42.0″ tall and 13.5″ wide, and fits a 20″ wheel.

Diameter42.00″

Width13.50″

Sidewall11.00″

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

Manufacturer data

How tall 42×13.50R20 tires really are

Heights published by Mickey Thompson for all 2 tires in this size.

Real 42×13.50R20 tires measure 41.70–41.80″, against 42.00″ from the size code. Every one runs shorter than the size code.

Mickey Thompson Baja Boss M/T41.80″ −0.20″
Mickey Thompson Baja Boss X41.70″ −0.30″

Each bar runs from the size code's 42.00″ (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.

Weight spread104.0–106.0 lb

The lightest (Mickey Thompson Baja Boss M/T, LT D) is 2.0 lb lighter per corner than the heaviest (Mickey Thompson Baja Boss X, LT C).

2 tires in 42×13.50R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Mickey Thompson Baja Boss M/TMud-terrain	LT D · 128Q	41.80	104.0	22.0	3,970	–	Spec page
Mickey Thompson Baja Boss X	LT C · 124F	41.70	106.0	22.0	3,525	–	Spec page

Is a 42×13.50R20 really 42 inches tall?

41.8″

Shorter. The name says 42″, and the 2 tires here publish 41.70–41.80″.

All 42-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 42×13.50R20	Difference
40×13.50R20	40.00	-2.00″	-4.8%
40×14.50R20	40.00	-2.00″	-4.8%
40×15.50R20	40.00	-2.00″	-4.8%
44×13.50R20	44.00	+2.00″	+4.8%

How to read 42×13.50R20

How to read any tire size

How 42X13.50R20LT 128Q is printed on the sidewall. It's the most common code among the 2 tires here (1 of them); tires in this size come in other load and speed ratings too.

142Overall diameter

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

213.50Section width

13.50 inches across the widest point, or 343 mm.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 9.0″ to 11.5″.

5LTLight truck

Marks a light truck (LT) tire.

6128Load index

Each tire carries up to 3,970 lb (1,800 kg) at its maximum pressure.

7QSpeed rating

Rated for up to 99 mph sustained.

DLoad range

Printed separately as "LOAD RANGE D": a 8-ply rating, inflated up to 65 psi (standard load-range table). The load range D tires here carry up to 3,970 lb each, as published.

Specification	Inches	Metric
Overall diameter	42.00	1067 mm
Section width	13.50	343 mm
Sidewall height	11.00	279.4 mm
Circumference	131.9	3,351 mm
Revolutions per mile (calculated, unloaded)	480.2	298 per km
Approved wheel width	9.0–11.5	229–292 mm

Speedometer error after switching to 42×13.50R20

Your actual speed– mph

Questions about 42×13.50R20

What is 42×13.50R20 in inches?

42.00 inches tall, 13.50 inches wide, on a 20-inch wheel. Manufacturers publish 41.70–41.80 inches for the 2 tires listed here.

How much does a 42×13.50R20 tire weigh?

Between 104.0 lb and 106.0 lb for the 2 tires listed here. The lightest is the Mickey Thompson Baja Boss M/T (LT D); the heaviest is the Mickey Thompson Baja Boss X (LT C).

What wheel width do I need for 42×13.50R20?

Manufacturers approve 9.0–11.5″ wide wheels for this size.

How much taller is 42×13.50R20 than 40×15.50R20?

2.00 inches taller on paper (42.00″ vs 40.00″), which raises the axle about 1.00″. Your speedometer will read about 5.0% slow.