tireheight.com

285/35R18 in inches

A 285/35R18 tire is 25.9″ tall and 11.2″ wide, and fits a 18″ wheel. In inches it is written 25.9×11.2R18.

Diameter25.85″
Width11.22″
Sidewall3.93″
285/35R18 drawn to scale: 25.85 inch diameter, 3.93 inch sidewall, 18 inch wheel, 11.22 inch tread width18″ wheel3.93″25.85″ overall11.22″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 285/35R18 tires really are

Heights published by General and Michelin for all 5 tires in this size. Their published revolutions per mile work out to 25.1–25.2″ under load (below).

Real 285/35R18 tires measure 25.90–26.00″, against 25.85″ from the size code. Every one runs taller than the size code.

  1. Michelin Pilot Sport All-Season 426.00″ +0.15″
  2. General G-MAX RS25.90″ +0.05″
  3. Michelin Pilot Sport 325.90″ +0.05″
  4. Michelin Pilot Sport 4 S25.90″ +0.05″
  5. Michelin Pilot Super Sport25.90″ +0.05″
Each bar runs from the size code's 25.85″ (the orange line) to the model's published height. The track spans 1.0″. Where a model comes in several load ranges, the darker part shows its range of heights; the number after the name is how many versions it comes in.
Height under load25.1–25.2″

Published revs per mile (801–804) mean the tire rolls like a 25.1–25.2″ tire on the vehicle. Use this for speedometer calibration.

Weight spread26.7–28.1 lb

The lightest (General G-MAX RS, XL) is 1.4 lb lighter per corner than the heaviest (Michelin Pilot Super Sport, XL).

5 tires in 285/35R18

Sort by the spec you care about.

LoadRevs/miSource
General G-MAX RSPerformanceXL · 101Y25.9026.710.01,819803Spec page
Michelin Pilot Sport 3PerformanceXL · 101(Y)25.9026.98.51,819804Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 101Y26.0027.210.01,819801Spec page
Michelin Pilot Sport 4 SPerformanceXL · 101(Y)25.9027.39.51,819804Spec page
Michelin Pilot Super SportPerformanceXL · 101(Y)25.9028.19.51,819804Spec page

Is 285/35R18 a 26-inch tire?

≈26″

Yes. The size code works out to 25.85″, and the 5 tires here publish 25.90–26.00″, so people call it a 26.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 285/35R18Difference
235/40R1825.40-0.45″-1.8%
315/30R1825.44-0.41″-1.6%
275/35R1825.58-0.28″-1.1%
215/45R1825.62-0.24″-0.9%
245/40R1825.72-0.14″-0.5%
335/30R1825.91+0.06″+0.2%
225/45R1825.97+0.12″+0.5%
255/40R1826.03+0.18″+0.7%
295/35R1826.13+0.28″+1.1%
235/45R1826.33+0.47″+1.8%

How to read 285/35R18

How to read any tire size

285/35R18 101Y as printed on the tire sidewall, with each part numbered285/35R18 101Y123456
How 285/35R18 101Y is printed on the sidewall. It's the most common code among the 5 tires here (3 of them); tires in this size come in other load and speed ratings too.
1285Section width

285 mm across the widest point, or 11.22 inches. Every 285 size

235Aspect ratio

A percentage, not a measurement: the sidewall is 35% as tall as the tire is wide, which is 99.8 mm or 3.93 inches.

3RConstruction

Radial construction.

418Wheel diameter

Mounts on a 18-inch wheel. Approved wheel widths run 9.5″ to 11.0″.

5101Load index

Each tire carries up to 1,819 lb (825 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size.

SpecificationInchesMetric
Overall diameter25.85657 mm
Section width11.22285 mm
Sidewall height3.9399.8 mm
Circumference81.22,063 mm
Revolutions per mile (calculated, unloaded)780.1485 per km
Revolutions per mile (published by manufacturers)801–804498–500 per km
Approved wheel width9.5–11.0241–279 mm

Speedometer error after switching to 285/35R18

Your actual speed– mph

Questions about 285/35R18

What is 285/35R18 in inches?

25.85 inches tall, 11.22 inches wide, on a 18-inch wheel. Written in inches, that is roughly 25.9×11.2R18.

How much does a 285/35R18 tire weigh?

Between 26.7 lb and 28.1 lb for the 5 tires listed here. The lightest is the General G-MAX RS (XL); the heaviest is the Michelin Pilot Super Sport (XL).

What wheel width do I need for 285/35R18?

Manufacturers approve 9.5–11.0″ wide wheels for this size.

How many revolutions per mile does a 285/35R18 make?

Published figures run 801–804 revolutions per mile. The calculated figure is 780.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 285/35R18 than 245/40R18?

0.14 inches taller on paper (25.85″ vs 25.72″), which raises the axle about 0.07″. Your speedometer will read about 0.5% slow.