245/30R20 in inches

A 245/30R20 tire is 25.8″ tall and 9.6″ wide, and fits a 20″ wheel. In inches it is written 25.8×9.6R20.

Diameter25.79″

Width9.65″

Sidewall2.89″

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

Manufacturer data

How tall 245/30R20 tires really are

Heights published by Michelin and Toyo for all 6 tires in this size. Their published revolutions per mile work out to 25.1″ under load (below).

Real 245/30R20 tires measure 25.80″, against 25.79″ from the size code. They run both taller and shorter than the size code.

Height under load25.1″

Published revs per mile (804–805) mean the tire rolls like a 25.1″ tire on the vehicle. Use this for speedometer calibration.

Weight spread21.4–24.5 lb

The lightest (Michelin Pilot Sport Cup 2 Connect, XL) is 3.1 lb lighter per corner than the heaviest (Michelin Pilot Sport All-Season 4, XL).

6 tires in 245/30R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 90(Y)	25.80	21.4	7.2	1,323	805	Spec page
Michelin Pilot Sport Cup 2Performance	XL · 90(Y)	25.80	21.9	7.2	1,323	805	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 90(Y)	25.80	22.7	9.5	1,323	805	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 90(Y)	25.80	22.7	9.0	1,323	805	Spec page
Toyo Proxes Sport 2Performance	XL · 90(Y)	25.80	22.7	8.9	1,323	804	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 90Y	25.80	24.5	10.0	1,323	805	Spec page

Is 245/30R20 a 26-inch tire?

≈26″

Yes. The size code works out to 25.79″, and the 6 tires here publish 25.80″, so people call it a 26.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 245/30R20	Difference
225/30R20	25.31	-0.47″	-1.8%
235/30R20	25.55	-0.24″	-0.9%
285/25R20	25.61	-0.18″	-0.7%
295/25R20	25.81	+0.02″	+0.1%
305/25R20	26.00	+0.22″	+0.8%
255/30R20	26.02	+0.24″	+0.9%
225/35R20	26.20	+0.41″	+1.6%
265/30R20	26.26	+0.47″	+1.8%
325/25R20	26.40	+0.61″	+2.4%
235/35R20	26.48	+0.69″	+2.7%

How to read 245/30R20

How to read any tire size

How 245/30R20 90Y is printed on the sidewall. It's the most common code among the 6 tires here (5 of them); tires in this size come in other load and speed ratings too.

1245Section width

245 mm across the widest point, or 9.65 inches. Every 245 size

230Aspect ratio

A percentage, not a measurement: the sidewall is 30% as tall as the tire is wide, which is 73.5 mm or 2.89 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.0″ to 9.0″.

590Load index

Each tire carries up to 1,323 lb (600 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size.

Specification	Inches	Metric
Overall diameter	25.79	655 mm
Section width	9.65	245 mm
Sidewall height	2.89	73.5 mm
Circumference	81.0	2,058 mm
Revolutions per mile (calculated, unloaded)	782.1	486 per km
Revolutions per mile (published by manufacturers)	804–805	500 per km
Approved wheel width	8.0–9.0	203–229 mm

Speedometer error after switching to 245/30R20

Your actual speed– mph

Questions about 245/30R20

What is 245/30R20 in inches?

25.79 inches tall, 9.65 inches wide, on a 20-inch wheel. Written in inches, that is roughly 25.8×9.6R20.

How much does a 245/30R20 tire weigh?

Between 21.4 lb and 24.5 lb for the 6 tires listed here. The lightest is the Michelin Pilot Sport Cup 2 Connect (XL); the heaviest is the Michelin Pilot Sport All-Season 4 (XL).

What wheel width do I need for 245/30R20?

Manufacturers approve 8.0–9.0″ wide wheels for this size.

How many revolutions per mile does a 245/30R20 make?

Published figures run 804–805 revolutions per mile. The calculated figure is 782.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 245/30R20 than 285/25R20?

0.18 inches taller on paper (25.79″ vs 25.61″), which raises the axle about 0.09″. Your speedometer will read about 0.7% slow.