265/70R18 Tire Size in Inches & Millimeters

Tire size “265/70R18” indicates your vehicle’s specifications based on tire width, aspect ratio, height, tire construction, diameter, radial and inches. These tire size numbers represent our tire sizes in both Metric (in millimeters) and Imperial (in inches) units of measurement to help find the correct tire size for your vehicle.

To convert tire size 265/70R18 to inches, you must know what these numbers represent.

So let us know 265/70R18 in simple words:

First number “265” indicates the tire’s width in millimeters.
Second number “70” refers to the aspect ratio, which is the height of the tire’s sidewall as a percentage of its width.
Third number “R18” refers to a tire that is designed to fit a 18-inch diameter rim.

Therefore, when converting the tire size 265/70R18 to inches, it can be concluded that the width of the tire will be approximately 10.4 inches ( 265 mm= 10.4 in), and the sidewall height will be approximately 7.3 inches (70% of 10.4 inches = 7.3 inches).

How to convert 265/70R18 into Inches (imperial)?

To convert tire size 265/70R18 to inches (Imperial) –

1. Width conversion: To convert it to inches, you can use a conversion factor of approximately 25.4 millimeters per inch.

  • 265 millimeters/25.4 = approximately 10.4 inches
    So, the width of the tire is approximately 10.4 inches.

2. Aspect Ratio Calculation: To calculate sidewall height in inches, you can use the tire width (from Step 1) and the aspect ratio:

  • Sidewall Height = Width (in inches) * Aspect Ratio / 100
  • Sidewall Height = 10.4 inches * 70/100 = approximately 7.3 inches
    So, the tire sidewall height is approximately 7.3 inches.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number “18” indicates the rim diameter in inches. In this case, it’s already in inches.
So, the converted tire size “265/70R18” in inches (imperial) is approximately:

  • Width: 10.4 inches
  • Sidewall Height: 7.3 inches
  • Rim Diameter: 18 inches

How to convert 265/70R18 into Millimeters (metric)?

To convert the tire size 265/70R18 into millimeters (metric) –

1. Width Conversion: The first number in the tire size, “265“, represents the tire’s width in millimeters. Since it’s already in millimeters, there’s no need for conversion.

  • Width: 265millimeters

2. Aspect Ratio Calculation: The second number “70” is the aspect ratio, representing the tire’s sidewall height as a percentage of its width. To calculate the sidewall height in millimeters, you can use the tire’s width (from step 1) and the aspect ratio:

  • Sidewall height = Width (in millimeters) * Aspect Ratio / 100
  • Sidewall height = 265 millimeters * 70 / 100 = 186 mm millimeters
    So, the tire’s sidewall height is approximately 186 mm millimeters.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number, “18” indicates the rim diameter in inches. To convert this to millimeters, you can use the conversion factor of approximately 25.4 millimeters per inch.

  • Rim diameter = 18 inches * 25.4 millimeters per inch = 457 mm millimeters
    So, the rim diameter is approximately 457 mm millimeters.

So, the converted tire size “265/70R18” in millimeters (metric) is approximately:

  • Width: 265 mm
  • Sidewall Height: 186 mm
  • Rim Diameter: 457 mm

Alternate Tire Size of 265/70R18 For replacement

Tire Size Overall Diameter Difference
235/75R18 31.9″ (809 mm) -2.4%
275/55R20 31.9″ (810 mm) -2.3%
225/70R19.5 31.9″ (811 mm) -2.2%
255/60R20 32″ (814 mm) -1.8%
305/50R20 32″ (814 mm) -1.8%
255/65R19 32.1″ (815 mm) -1.7%
255/70R18 32.1″ (815 mm) -1.7%
275/65R18 32.1″ (815 mm) -1.7%
285/55R20 32.4″ (822 mm) -0.8%
305/60R18 32.4″ (823 mm) -0.7%
315/50R20 32.4″ (824 mm) -0.6%
265/60R20 32.5″ (826 mm) -0.4%
285/65R18 32.6″ (827 mm) -0.2%
295/55R20 32.8″ (832 mm) 0.4%
375/50R18 32.8″ (833 mm) 0.5%
325/50R20 32.8″ (834 mm) 0.6%
275/60R20 33″ (838 mm) 1.1%
245/70R19.5 33″ (839 mm) 1.2%
295/65R18 33.1″ (841 mm) 1.4%
275/70R18 33.2″ (843 mm) 1.7%
305/55R20 33.2″ (844 mm) 1.8%
375/45R20 33.3″ (846 mm) 2.1%
325/60R18 33.3″ (847 mm) 2.2%
285/60R20 33.5″ (850 mm) 2.5%
305/65R18 33.6″ (853 mm) 2.9%

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