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265/45R18 in inches

A 265/45R18 tire is 27.4″ tall and 10.4″ wide, and fits a 18″ wheel. In inches it is written 27.4×10.4R18.

Diameter27.39″
Width10.43″
Sidewall4.69″
265/45R18 drawn to scale: 27.39 inch diameter, 4.69 inch sidewall, 18 inch wheel, 10.43 inch tread width18″ wheel4.69″27.39″ overall10.43″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 265/45R18 tires really are

Heights published by Michelin and Toyo for all 2 tires in this size. Their published revolutions per mile work out to 26.5–26.6″ under load (below).

Real 265/45R18 tires measure 27.36–27.40″, against 27.39″ from the size code. They run both taller and shorter than the size code.

Height under load26.5–26.6″

Published revs per mile (759–760) mean the tire rolls like a 26.5–26.6″ tire on the vehicle. Use this for speedometer calibration.

Weight spread28.2–29.6 lb

The lightest (Michelin Pilot Sport All-Season 4, XL) is 1.4 lb lighter per corner than the heaviest (Toyo Proxes Sport A/S, SL).

2 tires in 265/45R18

Sort by the spec you care about.

LoadRevs/miSource
Michelin Pilot Sport All-Season 4PerformanceXL · 104Y27.4028.210.01,984760Spec page
Toyo Proxes Sport A/SPerformanceSL · 101Y27.3629.69.71,819759Spec page

Is 265/45R18 a 27-inch tire?

≈27″

Close. The size code works out to 27.39″, and the 2 tires here publish 27.36–27.40″, so people call it a 27.

All 27-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 265/45R18Difference
245/45R1826.68-0.71″-2.6%
315/35R1826.68-0.71″-2.6%
225/50R1826.86-0.53″-1.9%
285/40R1826.98-0.41″-1.5%
255/45R1827.04-0.35″-1.3%
235/50R1827.25-0.14″-0.5%
215/55R1827.31-0.08″-0.3%
345/35R1827.51+0.12″+0.4%
245/50R1827.65+0.26″+0.9%
225/55R1827.74+0.35″+1.3%

How to read 265/45R18

How to read any tire size

265/45R18 104Y as printed on the tire sidewall, with each part numbered265/45R18 104Y123456
How 265/45R18 104Y 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.
1265Section width

265 mm across the widest point, or 10.43 inches. Every 265 size

245Aspect ratio

A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 119.3 mm or 4.69 inches.

3RConstruction

Radial construction.

418Wheel diameter

Mounts on a 18-inch wheel. Approved wheel widths run 8.5″ to 10.0″.

5104Load index

Each tire carries up to 1,984 lb (900 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 1,984 lb each and the standard-load tires up to 1,819 lb, as published.

SpecificationInchesMetric
Overall diameter27.39696 mm
Section width10.43265 mm
Sidewall height4.69119.3 mm
Circumference86.02,186 mm
Revolutions per mile (calculated, unloaded)736.3458 per km
Revolutions per mile (published by manufacturers)759–760472 per km
Approved wheel width8.5–10.0216–254 mm

Speedometer error after switching to 265/45R18

Your actual speed– mph

Questions about 265/45R18

What is 265/45R18 in inches?

27.39 inches tall, 10.43 inches wide, on a 18-inch wheel. Written in inches, that is roughly 27.4×10.4R18.

How much does a 265/45R18 tire weigh?

Between 28.2 lb and 29.6 lb for the 2 tires listed here. The lightest is the Michelin Pilot Sport All-Season 4 (XL); the heaviest is the Toyo Proxes Sport A/S (SL).

What wheel width do I need for 265/45R18?

Manufacturers approve 8.5–10.0″ wide wheels for this size.

How many revolutions per mile does a 265/45R18 make?

Published figures run 759–760 revolutions per mile. The calculated figure is 736.3, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 265/45R18 than 215/55R18?

0.08 inches taller on paper (27.39″ vs 27.31″), which raises the axle about 0.04″. Your speedometer will read about 0.3% slow.