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255/45R17 in inches

A 255/45R17 tire is 26.0″ tall and 10.0″ wide, and fits a 17″ wheel. In inches it is written 26.0×10.0R17.

Diameter26.04″
Width10.04″
Sidewall4.52″
255/45R17 drawn to scale: 26.04 inch diameter, 4.52 inch sidewall, 17 inch wheel, 10.04 inch tread width17″ wheel4.52″26.04″ overall10.04″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 255/45R17 tires really are

Heights published by Michelin and Toyo for all 2 tires in this size. Their published revolutions per mile work out to 25.3″ under load (below).

Real 255/45R17 tires measure 26.06–26.10″, against 26.04″ from the size code. Every one runs taller than the size code.

Height under load25.3″

Published revs per mile (797–798) mean the tire rolls like a 25.3″ tire on the vehicle. Use this for speedometer calibration.

Weight spread26.7–27.1 lb

The lightest (Michelin Pilot Sport All-Season 4, XL) is 0.4 lb lighter per corner than the heaviest (Toyo Extensa HP II, SL).

2 tires in 255/45R17

Sort by the spec you care about.

LoadRevs/miSource
Michelin Pilot Sport All-Season 4PerformanceXL · 102Y26.1026.710.01,874798Spec page
Toyo Extensa HP IIPerformanceSL · 98W26.0627.19.71,653797Spec page

Is 255/45R17 a 26-inch tire?

≈26″

Yes. The size code works out to 26.04″, and the 2 tires here publish 26.06–26.10″, so people call it a 26.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 255/45R17Difference
215/50R1725.46-0.57″-2.2%
275/40R1725.66-0.37″-1.4%
245/45R1725.68-0.35″-1.4%
315/35R1725.68-0.35″-1.4%
225/50R1725.86-0.18″-0.7%
205/55R1725.88-0.16″-0.6%
195/60R1726.21+0.18″+0.7%
335/35R1726.23+0.20″+0.8%
235/50R1726.25+0.22″+0.8%
215/55R1726.31+0.28″+1.1%

How to read 255/45R17

How to read any tire size

255/45R17 102Y as printed on the tire sidewall, with each part numbered255/45R17 102Y123456
How 255/45R17 102Y is printed on the sidewall. It's the most common code among the 2 tires here (1 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.

417Wheel diameter

Mounts on a 17-inch wheel. Approved wheel widths run 8.0″ to 9.5″.

5102Load index

Each tire carries up to 1,874 lb (850 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 1,874 lb each and the standard-load tires up to 1,653 lb, as published.

SpecificationInchesMetric
Overall diameter26.04661 mm
Section width10.04255 mm
Sidewall height4.52114.8 mm
Circumference81.82,078 mm
Revolutions per mile (calculated, unloaded)774.6481 per km
Revolutions per mile (published by manufacturers)797–798495–496 per km
Approved wheel width8.0–9.5203–241 mm

Speedometer error after switching to 255/45R17

Your actual speed– mph

Questions about 255/45R17

What is 255/45R17 in inches?

26.04 inches tall, 10.04 inches wide, on a 17-inch wheel. Written in inches, that is roughly 26.0×10.0R17.

How much does a 255/45R17 tire weigh?

Between 26.7 lb and 27.1 lb for the 2 tires listed here. The lightest is the Michelin Pilot Sport All-Season 4 (XL); the heaviest is the Toyo Extensa HP II (SL).

What wheel width do I need for 255/45R17?

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

How many revolutions per mile does a 255/45R17 make?

Published figures run 797–798 revolutions per mile. The calculated figure is 774.6, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/45R17 than 205/55R17?

0.16 inches taller on paper (26.04″ vs 25.88″), which raises the axle about 0.08″. Your speedometer will read about 0.6% slow.