255/45R20 in inches

A 255/45R20 tire is 29.0″ tall and 10.0″ wide, and fits a 20″ wheel. In inches it is written 29.0×10.0R20.

Diameter29.04″

Width10.04″

Sidewall4.52″

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

Manufacturer data

How tall 255/45R20 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 29 tires in this size. Their published revolutions per mile work out to 28.2″ under load (below).

Real 255/45R20 tires measure 29.00–29.10″, against 29.04″ from the size code. Most run taller than the size code (24 of 29).

Height under load28.2″

Published revs per mile (715–716) mean the tire rolls like a 28.2″ tire on the vehicle. Use this for speedometer calibration.

Weight spread27.3–34.4 lb

The lightest (Michelin Pilot Sport 4 SUV, XL) is 7.1 lb lighter per corner than the heaviest (Toyo Observe G3-Ice, XL).

29 tires in 255/45R20

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport 4 SUVPerformance	XL · 105W	29.10	27.3	9.5	2,039	716	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 105W	29.10	27.3	9.5	2,039	716	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 105W	29.10	28.7	8.5	2,039	716	Spec page
Michelin Primacy Tour A/STouring	XL · 105V	29.10	28.7	8.5	2,039	716	Spec page
Michelin Primacy Tour A/STouring	XL · 105V	29.10	28.9	9.0	2,039	716	Spec page
Michelin Pilot Alpin 5Winter	XL · 105V	29.06	29.4	9.5	2,039	716	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 105(Y)	29.10	29.4	9.5	2,039	716	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 105W	29.10	29.4	8.5	2,039	716	Spec page
General G-MAX AS07Performance	XL · 105W	29.00	29.5	10.0	2,039	715	Spec page
Michelin CrossClimate2All-season	XL · 105V	29.10	29.5	10.0	2,039	716	Spec page
Michelin Defender2All-season	XL · 105V	29.06	29.7	10.5	2,039	716	Spec page
Toyo Proxes Sport 2Performance	XL · 105Y	29.10	30.4	9.2	2,039	715	Spec page
BFGoodrich Advantage ControlAll-season	SL · 101W	29.06	30.5	10.5	1,819	716	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 105Y	29.10	30.5	10.0	2,039	716	Spec page
Michelin CrossClimate2All-season	XL · 105W	29.10	30.6	9.5	2,039	716	Spec page
Michelin Pilot Alpin 5Winter	XL · 105V	29.06	30.6	10.5	2,039	716	Spec page
Michelin Pilot Alpin 5Winter	XL · 105V	29.06	30.7	10.5	2,039	716	Spec page
Michelin Pilot Sport 4 SUVPerformance	XL · 105Y	29.10	30.7	9.5	2,039	716	Spec page
Michelin Pilot Alpin 5Winter	XL · 105V	29.06	30.8	10.5	2,039	716	Spec page
Toyo Extensa HP IIPerformance	XL · 105W	29.05	31.0	9.7	2,039	715	Spec page
Michelin Latitude Sport 3Performance	XL · 105Y	29.10	31.0	8.5	2,039	716	Spec page
Michelin Latitude Sport 3Performance	XL · 105V	29.10	31.8	8.5	2,039	716	Spec page
Toyo Proxes G-Tour	XL · 105W	29.06	32.2	11.2	2,039	715	Spec page
BFGoodrich g-Force COMP-2 A/S PLUSPerformance	SL · 101Y	29.06	32.5	9.0	1,819	716	Spec page
Michelin X-Ice SnowWinter	XL · 105T	29.06	32.6	10.5	2,039	716	Spec page
Toyo Proxes Sport A/SPerformance	XL · 105Y	29.05	32.7	9.7	2,039	715	Spec page
Toyo Proxes ST IIIPerformance	XL · 105V	29.05	32.8	10.1	2,039	715	Spec page
Michelin X-Ice Snow+Winter	XL · 105H	29.06	33.0	10.5	2,039	716	Spec page
Toyo Observe G3-IceWinter	XL · 105T	29.05	34.4	12.0	2,039	715	Spec page

Is 255/45R20 a 29-inch tire?

≈29″

Yes. The size code works out to 29.04″, and the 29 tires here publish 29.00–29.10″, 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 255/45R20	Difference
305/35R20	28.41	-0.63″	-2.2%
275/40R20	28.66	-0.37″	-1.3%
245/45R20	28.68	-0.35″	-1.2%
315/35R20	28.68	-0.35″	-1.2%
285/40R20	28.98	-0.06″	-0.2%
235/50R20	29.25	+0.22″	+0.7%
295/40R20	29.29	+0.26″	+0.9%
265/45R20	29.39	+0.35″	+1.2%
305/40R20	29.61	+0.57″	+2.0%
245/50R20	29.65	+0.61″	+2.1%

How to read 255/45R20

How to read any tire size

How 255/45R20 105V is printed on the sidewall. It's the most common code among the 29 tires here (10 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

245Aspect ratio

A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 114.8 mm or 4.52 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.0″ to 9.5″.

5105Load index

Each tire carries up to 2,039 lb (925 kg) at its maximum pressure.

6VSpeed rating

Rated for up to 149 mph sustained.

XLExtra load

Printed after the size. In this size the XL tires carry up to 2,039 lb each and the standard-load tires up to 1,819 lb, as published.

Specification	Inches	Metric
Overall diameter	29.04	737 mm
Section width	10.04	255 mm
Sidewall height	4.52	114.8 mm
Circumference	91.2	2,317 mm
Revolutions per mile (calculated, unloaded)	694.6	432 per km
Revolutions per mile (published by manufacturers)	715–716	444–445 per km
Approved wheel width	8.0–9.5	203–241 mm

Speedometer error after switching to 255/45R20

Your actual speed– mph

Questions about 255/45R20

What is 255/45R20 in inches?

29.04 inches tall, 10.04 inches wide, on a 20-inch wheel. Written in inches, that is roughly 29.0×10.0R20.

How much does a 255/45R20 tire weigh?

Between 27.3 lb and 34.4 lb for the 29 tires listed here. The lightest is the Michelin Pilot Sport 4 SUV (XL); the heaviest is the Toyo Observe G3-Ice (XL).

What wheel width do I need for 255/45R20?

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

How many revolutions per mile does a 255/45R20 make?

Published figures run 715–716 revolutions per mile. The calculated figure is 694.6, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/45R20 than 285/40R20?

0.06 inches taller on paper (29.04″ vs 28.98″), which raises the axle about 0.03″. Your speedometer will read about 0.2% slow.