245/45R20 in inches

A 245/45R20 tire is 28.7″ tall and 9.6″ wide, and fits a 20″ wheel. In inches it is written 28.7×9.6R20.

Diameter28.68″

Width9.65″

Sidewall4.34″

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

Manufacturer data

How tall 245/45R20 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 26 tires in this size. Their published revolutions per mile work out to 27.8–27.9″ under load (below).

Real 245/45R20 tires measure 28.60–28.70″, against 28.68″ from the size code. They run both taller and shorter than the size code.

Height under load27.8–27.9″

Published revs per mile (724–726) mean the tire rolls like a 27.8–27.9″ tire on the vehicle. Use this for speedometer calibration.

Weight spread25.3–32.2 lb

The lightest (General AltiMAX RT45, SL) is 6.9 lb lighter per corner than the heaviest (Michelin Pilot Sport 4, SL).

26 tires in 245/45R20

Sort by the spec you care about.

	Load					Revs/mi	Source
General AltiMAX RT45Touring	SL · 99V	28.70	25.3	11.0	1,709	724	Spec page
Toyo Extensa HP IIPerformance	XL · 103W	28.66	25.4	9.6	1,929	725	Spec page
General G-MAX RSPerformance	XL · 103Y	28.70	25.8	10.0	1,929	724	Spec page
Michelin Pilot Alpin 5Winter	XL · 103V	28.66	26.8	9.5	1,929	726	Spec page
Michelin Pilot Alpin 5Winter	XL · 103V	28.66	26.9	9.5	1,929	726	Spec page
Toyo Proxes Sport 2Performance	XL · 103Y	28.70	26.9	9.2	1,929	725	Spec page
Michelin CrossClimate2All-season	XL · 103V	28.60	27.6	10.0	1,929	726	Spec page
Michelin Primacy Tour A/STouring	XL · 103V	28.70	28.0	8.5	1,929	726	Spec page
Michelin X-Ice SnowWinter	XL · 103H	28.66	28.0	10.5	1,929	726	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.70	28.2	9.5	1,929	726	Spec page
General G-MAX AS07Performance	XL · 103W	28.70	28.4	10.0	1,929	724	Spec page
BFGoodrich g-Force Phenom T/APerformance	XL · 103Y	28.66	28.6	8.0	1,929	726	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 103Y	28.70	28.6	10.0	1,929	726	Spec page
Michelin X-Ice Snow+Winter	XL · 103H	28.66	28.7	10.5	1,929	726	Spec page
Michelin Pilot Sport 4Performance	XL · 103Y	28.70	29.0	9.5	1,929	726	Spec page
Michelin Primacy Tour A/STouring	XL · 103W	28.70	29.8	8.5	1,929	726	Spec page
Toyo Celsius SportPerformance	XL · 103W	28.66	29.9	9.9	1,929	725	Spec page
Toyo Proxes G-Tour	XL · 103W	28.70	30.2	8.8	1,929	725	Spec page
BFGoodrich Advantage ControlAll-season	SL · 99V	28.66	30.3	10.5	1,709	726	Spec page
Toyo Celsius IITouring	XL · 103V	28.66	31.2	11.3	1,929	725	Spec page
BFGoodrich g-Force COMP-2 A/S PLUSPerformance	XL · 103Y	28.66	31.3	9.0	1,929	726	Spec page
Toyo Observe G3-IceWinter	SL · 99T	28.66	31.3	12.0	1,709	725	Spec page
Michelin Latitude Sport 3Performance	XL · 103W	28.70	31.5	8.5	1,929	726	Spec page
Toyo Proxes Sport A/SPerformance	XL · 103Y	28.66	31.9	9.6	1,929	725	Spec page
Michelin Pilot Sport 4Performance	SL · 99Y	28.70	32.2	9.0	1,709	726	Spec page
General AltiMAX Arctic XWinter	XL · 103T	28.70	–	12.0	1,929	724	Spec page

Is 245/45R20 a 29-inch tire?

≈29″

Yes. The size code works out to 28.68″, and the 26 tires here publish 28.60–28.70″, so people call it a 29.

All 29-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 245/45R20	Difference
295/35R20	28.13	-0.55″	-1.9%
345/30R20	28.15	-0.53″	-1.9%
235/45R20	28.33	-0.35″	-1.2%
265/40R20	28.35	-0.33″	-1.2%
305/35R20	28.41	-0.28″	-1.0%
275/40R20	28.66	-0.02″	-0.1%
315/35R20	28.68	0.00″	0.0%
285/40R20	28.98	+0.30″	+1.0%
255/45R20	29.04	+0.35″	+1.2%
235/50R20	29.25	+0.57″	+2.0%

How to read 245/45R20

How to read any tire size

How 245/45R20 103Y is printed on the sidewall. It's the most common code among the 26 tires here (7 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

245Aspect ratio

A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 110.2 mm or 4.34 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 7.5″ to 9.0″.

5103Load index

Each tire carries up to 1,929 lb (875 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 1,929 lb each and the standard-load tires up to 1,709 lb, as published.

Specification	Inches	Metric
Overall diameter	28.68	729 mm
Section width	9.65	245 mm
Sidewall height	4.34	110.2 mm
Circumference	90.1	2,289 mm
Revolutions per mile (calculated, unloaded)	703.2	437 per km
Revolutions per mile (published by manufacturers)	724–726	450–451 per km
Approved wheel width	7.5–9.0	191–229 mm

Speedometer error after switching to 245/45R20

Your actual speed– mph

Questions about 245/45R20

What is 245/45R20 in inches?

28.68 inches tall, 9.65 inches wide, on a 20-inch wheel. Written in inches, that is roughly 28.7×9.6R20.

How much does a 245/45R20 tire weigh?

Between 25.3 lb and 32.2 lb for the 25 tires listed here. The lightest is the General AltiMAX RT45 (SL); the heaviest is the Michelin Pilot Sport 4 (SL).

What wheel width do I need for 245/45R20?

Manufacturers approve 7.5–9.0″ wide wheels for this size.

How many revolutions per mile does a 245/45R20 make?

Published figures run 724–726 revolutions per mile. The calculated figure is 703.2, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 245/45R20 than 275/40R20?

0.02 inches taller on paper (28.68″ vs 28.66″), which raises the axle about 0.01″. Your speedometer will read about 0.1% slow.