265/65R18 Tire Size in Inches & Millimeters

Tire size “265/65R18” 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 265/65R18 to inches, you must know what these numbers represent.

So let us know 265/65R18 in simple words:

First number “265” indicates the tire’s width in millimeters.
Second number “65” 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 265/65R18 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 6.8 inches (65% of 10.4 inches = 6.8 inches).

How to convert 265/65R18 into Inches (imperial)?

To convert tire size 265/65R18 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 * 65/100 = approximately 6.8 inches
    So, the tire sidewall height is approximately 6.8 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 “265/65R18” in inches (imperial) is approximately:

  • Width: 10.4 inches
  • Sidewall Height: 6.8 inches
  • Rim Diameter: 18 inches

How to convert 265/65R18 into Millimeters (metric)?

To convert the tire size 265/65R18 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 “65” 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 * 65 / 100 = 172 mm millimeters
    So, the tire’s sidewall height is approximately 172 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 “265/65R18” in millimeters (metric) is approximately:

  • Width: 265 mm
  • Sidewall Height: 172 mm
  • Rim Diameter: 457 mm

Alternate Tire Size of 265/65R18 For replacement

Tire Size Overall Diameter Difference
165/90R19 30.7″ (781 mm) -2.5%
305/45R20 30.8″ (782 mm) -2.4%
275/50R20 30.9″ (784 mm) -2.1%
275/55R19 30.9″ (785 mm) -2%
235/70R18 31″ (787 mm) -1.7%
275/60R18 31″ (787 mm) -1.7%
255/55R20 31″ (788 mm) -1.6%
235/65R19 31.1″ (789 mm) -1.5%
255/65R18 31.1″ (789 mm) -1.5%
255/60R19 31.1″ (789 mm) -1.5%
285/50R20 31.3″ (794 mm) -0.9%
225/75R18 31.3″ (795 mm) -0.7%
285/55R19 31.4″ (797 mm) -0.5%
285/60R18 31.5″ (799 mm) -0.2%
245/70R18 31.5″ (801 mm) 0%
245/60R20 31.6″ (802 mm) 0.1%
295/50R20 31.7″ (804 mm) 0.4%
235/75R18 31.9″ (809 mm) 1%
275/55R20 31.9″ (810 mm) 1.1%
225/70R19.5 31.9″ (811 mm) 1.2%
305/50R20 32″ (814 mm) 1.6%
255/60R20 32″ (814 mm) 1.6%
275/65R18 32.1″ (815 mm) 1.7%
255/70R18 32.1″ (815 mm) 1.7%
255/65R19 32.1″ (815 mm) 1.7%
285/55R20 32.4″ (822 mm) 2.6%
305/60R18 32.4″ (823 mm) 2.7%
315/50R20 32.4″ (824 mm) 2.9%

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