255/50R20 in inches

A 255/50R20 tire is 30.0″ tall and 10.0″ wide, and fits a 20″ wheel. In inches it is written 30.0×10.0R20.

Diameter30.04″

Width10.04″

Sidewall5.02″

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

Manufacturer data

How tall 255/50R20 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 22 tires in this size. Their published revolutions per mile work out to 29.1–29.2″ under load (below).

Real 255/50R20 tires measure 30.00–30.10″, against 30.04″ from the size code. They run both taller and shorter than the size code.

Height under load29.1–29.2″

Published revs per mile (691–692) mean the tire rolls like a 29.1–29.2″ tire on the vehicle. Use this for speedometer calibration.

Weight spread31.1–37.5 lb

The lightest (Michelin Primacy All Season, SL) is 6.4 lb lighter per corner than the heaviest (BFGoodrich Advantage Control, XL).

22 tires in 255/50R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Primacy All SeasonTouring	SL · 105H	30.10	31.1	8.5	2,039	691	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 109Y	30.10	31.7	9.5	2,271	691	Spec page
Michelin Pilot Sport EVPerformance	XL · 109W	30.10	31.8	8.0	2,271	691	Spec page
Michelin CrossClimate2All-season	XL · 109V	30.00	32.0	10.0	2,271	691	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 109Y	30.10	32.3	10.0	2,271	691	Spec page
Michelin X-Ice SnowWinter	XL · 109T	30.08	32.3	10.5	2,271	691	Spec page
Michelin Defender2All-season	XL · 109H	30.00	32.6	10.5	2,271	691	Spec page
Michelin X-Ice Snow+Winter	XL · 109H	30.08	33.0	10.5	2,271	691	Spec page
General Grabber H/THighway	SL · 105T	30.00	33.4	12.0	2,039	692	Spec page
Michelin Latitude Tour HPAll-season	XL · 109W	30.00	34.1	9.5	2,064	691	Spec page
Toyo Proxes ST IIIPerformance	XL · 109V	30.08	34.4	10.1	2,271	691	Spec page
Toyo Celsius SportPerformance	XL · 109V	30.08	34.5	10.6	2,271	691	Spec page
Toyo Extensa A/S IIAll-season	XL · 109H	30.08	34.8	11.8	2,271	691	Spec page
Toyo Proxes G-Tour	XL · 109W	30.10	35.3	11.3	2,271	691	Spec page
Toyo Celsius IITouring	XL · 109V	30.08	35.5	11.5	2,271	691	Spec page
Toyo OPEN COUNTRY Q/TAll-season	XL · 109V	30.08	36.3	12.2	2,271	691	Spec page
General Grabber H/THighway	XL · 109H	30.00	36.4	12.0	2,271	692	Spec page
Toyo Observe G3-IceWinter	XL · 109T	30.08	36.6	12.0	2,271	691	Spec page
Toyo Open Country A/T IIIAll-terrain	XL · 109T	30.08	36.9	13.2	2,271	691	Spec page
Toyo Open Country H/T IIHighway	XL · 109H	30.08	37.5	10.8	2,271	691	Spec page
BFGoodrich Advantage ControlAll-season	XL · 109H	30.08	37.5	11.5	2,271	691	Spec page
General Grabber Arctic XWinter	XL · 109T	30.00	–	12.0	2,271	692	Spec page

Is 255/50R20 a 30-inch tire?

≈30″

Yes. The size code works out to 30.04″, and the 22 tires here publish 30.00–30.10″, so people call it a 30.

All 30-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 255/50R20	Difference
295/40R20	29.29	-0.75″	-2.5%
265/45R20	29.39	-0.65″	-2.2%
305/40R20	29.61	-0.43″	-1.4%
245/50R20	29.65	-0.39″	-1.3%
275/45R20	29.74	-0.30″	-1.0%
255/45R21	30.04	-0.00″	-0.0%
285/45R20	30.10	+0.06″	+0.2%
235/55R20	30.18	+0.14″	+0.5%
265/50R20	30.43	+0.39″	+1.3%
295/45R20	30.45	+0.41″	+1.4%

How to read 255/50R20

How to read any tire size

How 255/50R20 109H is printed on the sidewall. It's the most common code among the 22 tires here (6 of them); tires in this size come in other load and speed ratings too.

1255Section width

255 mm across the widest point, or 10.04 inches. Every 255 size

250Aspect ratio

A percentage, not a measurement: the sidewall is 50% as tall as the tire is wide, which is 127.5 mm or 5.02 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 7.0″ to 9.0″.

5109Load index

Each tire carries up to 2,271 lb (1,030 kg) at its maximum pressure.

6HSpeed rating

Rated for up to 130 mph sustained.

XLExtra load

Printed after the size. In this size the XL tires carry up to 2,271 lb each and the standard-load tires up to 2,039 lb, as published.

Specification	Inches	Metric
Overall diameter	30.04	763 mm
Section width	10.04	255 mm
Sidewall height	5.02	127.5 mm
Circumference	94.4	2,397 mm
Revolutions per mile (calculated, unloaded)	671.4	417 per km
Revolutions per mile (published by manufacturers)	691–692	429–430 per km
Approved wheel width	7.0–9.0	178–229 mm

Speedometer error after switching to 255/50R20

Your actual speed– mph

Questions about 255/50R20

What is 255/50R20 in inches?

30.04 inches tall, 10.04 inches wide, on a 20-inch wheel. Written in inches, that is roughly 30.0×10.0R20.

How much does a 255/50R20 tire weigh?

Between 31.1 lb and 37.5 lb for the 21 tires listed here. The lightest is the Michelin Primacy All Season (SL); the heaviest is the BFGoodrich Advantage Control (XL).

What wheel width do I need for 255/50R20?

Manufacturers approve 7.0–9.0″ wide wheels for this size.

How many revolutions per mile does a 255/50R20 make?

Published figures run 691–692 revolutions per mile. The calculated figure is 671.4, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/50R20 than 275/45R20?

0.30 inches taller on paper (30.04″ vs 29.74″), which raises the axle about 0.15″. Your speedometer will read about 1.0% slow.