315/35R20 in inches

A 315/35R20 tire is 28.7″ tall and 12.4″ wide, and fits a 20″ wheel. In inches it is written 28.7×12.4R20.

Diameter28.68″

Width12.40″

Sidewall4.34″

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

Manufacturer data

How tall 315/35R20 tires really are

Heights published by Michelin and Toyo for all 14 tires in this size. Their published revolutions per mile work out to 27.8″ under load (below).

Real 315/35R20 tires measure 28.66–28.70″, against 28.68″ from the size code. They run both taller and shorter than the size code.

Height under load27.8″

Published revs per mile (725–726) mean the tire rolls like a 27.8″ tire on the vehicle. Use this for speedometer calibration.

Weight spread31.3–39.0 lb

The lightest (Michelin Pilot Sport Cup 2 R, XL) is 7.7 lb lighter per corner than the heaviest (Michelin Pilot Sport 4 SUV, XL).

14 tires in 315/35R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport Cup 2 RPerformance	XL · 110(Y)	28.70	31.3	5.5	2,337	726	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 110(Y)	28.70	32.6	9.0	2,337	726	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 110V	28.70	32.6	9.0	2,337	726	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 110(Y)	28.70	33.1	9.5	2,337	726	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 110Y	28.70	33.4	10.0	2,337	726	Spec page
Michelin Pilot Super SportPerformance	XL · 110(Y)	28.70	33.4	7.0	2,337	726	Spec page
Michelin Pilot Sport 4Performance	XL · 110(Y)	28.70	33.7	9.5	2,337	726	Spec page
Toyo Proxes Sport 2Performance	XL · 110Y	28.70	33.7	9.2	2,337	725	Spec page
Michelin Pilot Alpin PA4Winter	XL · 110V	28.66	34.4	10.5	2,337	726	Spec page
Michelin Pilot Alpin 5Winter	XL · 110V	28.66	34.6	9.5	2,337	726	Spec page
Toyo Celsius SportPerformance	XL · 110Y	28.66	36.7	9.7	2,337	725	Spec page
Toyo Proxes ST IIIPerformance	XL · 110W	28.66	37.3	10.1	2,337	725	Spec page
Michelin X-Ice SnowWinter	XL · 110H	28.66	38.4	10.5	2,337	726	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 110Y	28.70	39.0	9.0	2,337	726	Spec page

Is 315/35R20 a 29-inch tire?

≈29″

Yes. The size code works out to 28.68″, and the 14 tires here publish 28.66–28.70″, 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 315/35R20	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%
245/45R20	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 315/35R20

How to read any tire size

How 315/35R20 110Y is printed on the sidewall. It's the most common code among the 14 tires here (5 of them); tires in this size come in other load and speed ratings too.

1315Section width

315 mm across the widest point, or 12.40 inches. Every 315 size

235Aspect ratio

A percentage, not a measurement: the sidewall is 35% 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 10.5″ to 12.5″.

5110Load index

Each tire carries up to 2,337 lb (1,060 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	28.68	729 mm
Section width	12.40	315 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)	725–726	450–451 per km
Approved wheel width	10.5–12.5	267–318 mm

Speedometer error after switching to 315/35R20

Your actual speed– mph

Questions about 315/35R20

What is 315/35R20 in inches?

28.68 inches tall, 12.40 inches wide, on a 20-inch wheel. Written in inches, that is roughly 28.7×12.4R20.

How much does a 315/35R20 tire weigh?

Between 31.3 lb and 39.0 lb for the 14 tires listed here. The lightest is the Michelin Pilot Sport Cup 2 R (XL); the heaviest is the Michelin Pilot Sport 4 SUV (XL).

What wheel width do I need for 315/35R20?

Manufacturers approve 10.5–12.5″ wide wheels for this size.

How many revolutions per mile does a 315/35R20 make?

Published figures run 725–726 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 315/35R20 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.