245/35R21 in inches

A 245/35R21 tire is 27.8″ tall and 9.6″ wide, and fits a 21″ wheel. In inches it is written 27.8×9.6R21.

Diameter27.75″

Width9.65″

Sidewall3.38″

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

Manufacturer data

How tall 245/35R21 tires really are

Heights published by Michelin and Toyo for all 9 tires in this size. Their published revolutions per mile work out to 26.9–27.0″ under load (below).

Real 245/35R21 tires measure 27.76–27.80″, against 27.75″ from the size code. They run both taller and shorter than the size code.

Height under load26.9–27.0″

Published revs per mile (748–749) mean the tire rolls like a 26.9–27.0″ tire on the vehicle. Use this for speedometer calibration.

Weight spread24.5–29.2 lb

The lightest (Michelin Pilot Sport 4 S, XL) is 4.7 lb lighter per corner than the heaviest (Michelin X-Ice Snow, XL).

9 tires in 245/35R21

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport 4 SPerformance	XL · 96Y	27.80	24.5	9.0	1,565	749	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 96(Y)	27.80	25.3	9.5	1,565	749	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 96Y	27.80	26.4	10.0	1,565	749	Spec page
Toyo Proxes Sport A/SPerformance	XL · 96(Y)	27.76	26.9	9.3	1,565	748	Spec page
Toyo Proxes Sport 2Performance	XL · 96(Y)	27.80	27.6	9.1	1,565	748	Spec page
Toyo Proxes Sport A/SPerformance	XL · 99(Y)	27.80	28.0	10.1	1,709	748	Spec page
Michelin Pilot Super SportPerformance	XL · 96(Y)	27.80	28.5	9.5	1,565	749	Spec page
Michelin X-Ice Snow+Winter	XL · 96H	27.76	28.6	10.5	1,565	749	Spec page
Michelin X-Ice SnowWinter	XL · 96H	27.76	29.2	10.5	1,565	749	Spec page

Is 245/35R21 a 28-inch tire?

≈28″

Yes. The size code works out to 27.75″, and the 9 tires here publish 27.76–27.80″, so people call it a 28.

All 28-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 245/35R21	Difference
265/30R21	27.26	-0.49″	-1.8%
325/25R21	27.40	-0.35″	-1.3%
275/30R21	27.50	-0.26″	-0.9%
285/30R21	27.73	-0.02″	-0.1%
345/25R21	27.79	+0.04″	+0.1%
295/30R21	27.97	+0.22″	+0.8%
355/25R21	27.99	+0.24″	+0.9%
255/35R21	28.03	+0.28″	+1.0%
305/30R21	28.20	+0.45″	+1.6%
265/35R21	28.30	+0.55″	+2.0%

How to read 245/35R21

How to read any tire size

How 245/35R21 96Y is printed on the sidewall. It's the most common code among the 9 tires here (4 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

235Aspect ratio

A percentage, not a measurement: the sidewall is 35% as tall as the tire is wide, which is 85.8 mm or 3.38 inches.

3RConstruction

Radial construction.

421Wheel diameter

Mounts on a 21-inch wheel. Approved wheel widths run 8.0″ to 9.5″.

596Load index

Each tire carries up to 1,565 lb (710 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	27.75	705 mm
Section width	9.65	245 mm
Sidewall height	3.38	85.8 mm
Circumference	87.2	2,215 mm
Revolutions per mile (calculated, unloaded)	726.7	452 per km
Revolutions per mile (published by manufacturers)	748–749	465 per km
Approved wheel width	8.0–9.5	203–241 mm

Speedometer error after switching to 245/35R21

Your actual speed– mph

Questions about 245/35R21

What is 245/35R21 in inches?

27.75 inches tall, 9.65 inches wide, on a 21-inch wheel. Written in inches, that is roughly 27.8×9.6R21.

How much does a 245/35R21 tire weigh?

Between 24.5 lb and 29.2 lb for the 9 tires listed here. The lightest is the Michelin Pilot Sport 4 S (XL); the heaviest is the Michelin X-Ice Snow (XL).

What wheel width do I need for 245/35R21?

Manufacturers approve 8.0–9.5″ wide wheels for this size.

How many revolutions per mile does a 245/35R21 make?

Published figures run 748–749 revolutions per mile. The calculated figure is 726.7, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 245/35R21 than 285/30R21?

0.02 inches taller on paper (27.75″ vs 27.73″), which raises the axle about 0.01″. Your speedometer will read about 0.1% slow.