285/30R20 in inches

A 285/30R20 tire is 26.7″ tall and 11.2″ wide, and fits a 20″ wheel. In inches it is written 26.7×11.2R20.

Diameter26.73″

Width11.22″

Sidewall3.37″

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

Manufacturer data

How tall 285/30R20 tires really are

Heights published by General, Michelin and Toyo for all 26 tires in this size. Their published revolutions per mile work out to 26.0″ under load (below).

Real 285/30R20 tires measure 26.70–26.80″, against 26.73″ from the size code. Most run taller than the size code (25 of 26).

Height under load26.0″

Published revs per mile (776–777) mean the tire rolls like a 26.0″ tire on the vehicle. Use this for speedometer calibration.

Weight spread23.9–32.3 lb

The lightest (Michelin Pilot Sport Cup 2 R, XL) is 8.4 lb lighter per corner than the heaviest (Michelin Pilot Super Sport, SL).

26 tires in 285/30R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport Cup 2 RPerformance	XL · 99(Y)	26.80	23.9	5.5	1,709	777	Spec page
Michelin Pilot Super SportPerformance	XL · 99(Y)	26.80	24.5	7.0	1,709	777	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 99(Y)	26.80	24.6	7.2	1,709	777	Spec page
Michelin Pilot Alpin 5Winter	XL · 99V	26.77	25.2	9.5	1,708	777	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 99(Y)	26.80	25.4	9.0	1,709	777	Spec page
Michelin Pilot Sport Cup 2 RPerformance	XL · 99(Y)	26.80	26.5	5.5	1,709	777	Spec page
Michelin Pilot Super SportPerformance	XL · 99(Y)	26.80	26.8	9.0	1,709	777	Spec page
Toyo Proxes RPerformance	SL · 95(Y)	26.80	26.8	3.7	1,521	776	Spec page
General G-MAX RSPerformance	XL · 99Y	26.70	27.1	10.0	1,709	777	Spec page
Michelin Pilot Sport Cup 2Performance	XL · 99(Y)	26.80	27.3	7.2	1,709	777	Spec page
Michelin Pilot Sport Cup 2Performance	XL · 99(Y)	26.80	27.3	7.2	1,709	777	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 99(Y)	26.80	27.4	9.0	1,709	777	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 99(Y)	26.80	27.5	9.5	1,709	777	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 99(Y)	26.80	27.6	9.5	1,709	777	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 99(Y)	26.80	27.8	7.2	1,709	777	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 99(Y)	26.80	27.8	7.2	1,709	777	Spec page
Toyo Proxes Sport 2Performance	XL · 99(Y)	26.80	28.0	9.2	1,709	776	Spec page
Michelin Pilot Sport S 5Performance	XL · 99(Y)	26.80	28.1	9.0	1,709	777	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 99(Y)	26.80	28.4	7.2	1,709	777	Spec page
Toyo Proxes RRPerformance	SL · 95(Y)	26.77	28.7	3.6	1,521	776	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 99Y	26.80	28.9	10.0	1,709	777	Spec page
Toyo Proxes Sport A/SPerformance	XL · 99Y	26.77	29.7	9.6	1,709	776	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 99(Y)	26.80	30.1	7.2	1,709	777	Spec page
Michelin Pilot Sport All-Season 4Performance	SL · 95(Y)	26.80	31.3	10.0	1,521	777	Spec page
Toyo Proxes R888RPerformance	SL · 95(Y)	26.77	31.3	6.3	1,521	776	Spec page
Michelin Pilot Super SportPerformance	SL · 95(Y)	26.80	32.3	9.0	1,521	777	Spec page

Is 285/30R20 a 27-inch tire?

≈27″

Yes. The size code works out to 26.73″, and the 26 tires here publish 26.70–26.80″, so people call it a 27.

All 27-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 285/30R20	Difference
265/30R20	26.26	-0.47″	-1.8%
325/25R20	26.40	-0.33″	-1.3%
235/35R20	26.48	-0.26″	-1.0%
275/30R20	26.50	-0.24″	-0.9%
335/25R20	26.59	-0.14″	-0.5%
245/35R20	26.75	+0.02″	+0.1%
295/30R20	26.97	+0.24″	+0.9%
255/35R20	27.03	+0.30″	+1.1%
225/40R20	27.09	+0.35″	+1.3%
305/30R20	27.20	+0.47″	+1.8%

How to read 285/30R20

How to read any tire size

How 285/30R20 99Y is printed on the sidewall. It's the most common code among the 26 tires here (17 of them); tires in this size come in other load and speed ratings too.

1285Section width

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

230Aspect ratio

A percentage, not a measurement: the sidewall is 30% as tall as the tire is wide, which is 85.5 mm or 3.37 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 9.5″ to 10.5″.

599Load index

Each tire carries up to 1,709 lb (775 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size. In this size the XL tires carry up to 1,709 lb each and the standard-load tires up to 1,521 lb, as published.

Specification	Inches	Metric
Overall diameter	26.73	679 mm
Section width	11.22	285 mm
Sidewall height	3.37	85.5 mm
Circumference	84.0	2,133 mm
Revolutions per mile (calculated, unloaded)	754.4	469 per km
Revolutions per mile (published by manufacturers)	776–777	482–483 per km
Approved wheel width	9.5–10.5	241–267 mm

Speedometer error after switching to 285/30R20

Your actual speed– mph

Questions about 285/30R20

What is 285/30R20 in inches?

26.73 inches tall, 11.22 inches wide, on a 20-inch wheel. Written in inches, that is roughly 26.7×11.2R20.

How much does a 285/30R20 tire weigh?

Between 23.9 lb and 32.3 lb for the 26 tires listed here. The lightest is the Michelin Pilot Sport Cup 2 R (XL); the heaviest is the Michelin Pilot Super Sport (SL).

What wheel width do I need for 285/30R20?

Manufacturers approve 9.5–10.5″ wide wheels for this size.

How many revolutions per mile does a 285/30R20 make?

Published figures run 776–777 revolutions per mile. The calculated figure is 754.4, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 285/30R20 than 335/25R20?

0.14 inches taller on paper (26.73″ vs 26.59″), which raises the axle about 0.07″. Your speedometer will read about 0.5% slow.