LT285/75R18 Tire Size in Inches & Millimeters

Tire size “285/75R18” 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 LT285/75R18 to inches, you must know what these numbers represent.

So let us know LT285/75R18 in simple words:

First number “285” indicates the tire’s width in millimeters.
Second number “75” 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 LT285/75R18 to inches, it can be concluded that the width of the tire will be approximately 11.2 inches ( 285 mm= 11.2 in), and the sidewall height will be approximately 8.4 inches (75% of 11.2 inches = 8.4 inches).

How to convert LT285/75R18 into Inches (imperial)?

To convert tire size LT285/75R18 to inches (Imperial) –

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

  • 285 millimeters/25.4 = approximately 11.2 inches
    So, the width of the tire is approximately 11.2 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 = 11.2 inches * 75/100 = approximately 8.4 inches
    So, the tire sidewall height is approximately 8.4 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 “LT285/75R18” in inches (imperial) is approximately:

  • Width: 11.2 inches
  • Sidewall Height: 8.4 inches
  • Rim Diameter: 18 inches

How to convert LT285/75R18 into Millimeters (metric)?

To convert the tire size LT285/75R18 into millimeters (metric) –

1. Width Conversion: The first number in the tire size, “285“, represents the tire’s width in millimeters. Since it’s already in millimeters, there’s no need for conversion.

  • Width: 285millimeters

2. Aspect Ratio Calculation: The second number “75” 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 = 285 millimeters * 75 / 100 = 214 mm millimeters
    So, the tire’s sidewall height is approximately 214 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 “LT285/75R18” in millimeters (metric) is approximately:

  • Width: 285 mm
  • Sidewall Height: 214 mm
  • Rim Diameter: 457 mm

Alternate Tire Size of LT285/75R18 For replacement

Tire Size Overall Diameter Difference
295/60R20 33.9″ (862 mm) -2.6%
355/50R20 34″ (864 mm) -2.4%
275/65R20 34.1″ (866 mm) -2.1%
295/70R18 34.3″ (871 mm) -1.6%
345/60R18 34.3″ (871 mm) -1.6%
305/60R20 34.4″ (874 mm) -1.2%
335/55R20 34.5″ (876 mm) -1%
285/65R20 34.6″ (878 mm) -0.8%
325/65R18 34.6″ (879 mm) -0.7%
305/70R18 34.8″ (885 mm) 0%
315/60R20 34.9″ (886 mm) 0.1%
295/65R20 35.1″ (892 mm) 0.8%
275/80R18 35.3″ (897 mm) 1.4%
325/60R20 35.4″ (898 mm) 1.5%
315/70R18 35.4″ (899 mm) 1.6%
375/60R18 35.7″ (907 mm) 2.5%

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