255/45R19 Tire Size in Inches & Millimeters

Tire size “255/45R19” 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 255/45R19 to inches, you must know what these numbers represent.

So let us know 255/45R19 in simple words:

First number “255” indicates the tire’s width in millimeters.
Second number “45” refers to the aspect ratio, which is the height of the tire’s sidewall as a percentage of its width.
Third number “R19” refers to a tire that is designed to fit a 19-inch diameter rim.

Therefore, when converting the tire size 255/45R19 to inches, it can be concluded that the width of the tire will be approximately 10 inches ( 255 mm= 10 in), and the sidewall height will be approximately 4.5 inches (45% of 10 inches = 4.5 inches).

How to convert 255/45R19 into Inches (imperial)?

To convert tire size 255/45R19 to inches (Imperial) –

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

  • 255 millimeters/25.4 = approximately 10 inches
    So, the width of the tire is approximately 10 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 inches * 45/100 = approximately 4.5 inches
    So, the tire sidewall height is approximately 4.5 inches.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number “19” indicates the rim diameter in inches. In this case, it’s already in inches.
So, the converted tire size “255/45R19” in inches (imperial) is approximately:

  • Width: 10 inches
  • Sidewall Height: 4.5 inches
  • Rim Diameter: 19 inches

How to convert 255/45R19 into Millimeters (metric)?

To convert the tire size 255/45R19 into millimeters (metric) –

1. Width Conversion: The first number in the tire size, “255“, represents the tire’s width in millimeters. Since it’s already in millimeters, there’s no need for conversion.

  • Width: 255millimeters

2. Aspect Ratio Calculation: The second number “45” 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 = 255 millimeters * 45 / 100 = 115 mm millimeters
    So, the tire’s sidewall height is approximately 115 mm millimeters.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number, “19” 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 = 19 inches * 25.4 millimeters per inch = 483 mm millimeters
    So, the rim diameter is approximately 483 mm millimeters.

So, the converted tire size “255/45R19” in millimeters (metric) is approximately:

  • Width: 255 mm
  • Sidewall Height: 115 mm
  • Rim Diameter: 483 mm

Alternate Tire Size of 255/45R19 For replacement

Tire Size Overall Diameter Difference
305/30R20 27.2″ (692 mm) -2.9%
265/30R21 27.3″ (693 mm) -2.8%
175/60R19 27.3″ (693 mm) -2.8%
155/60R20 27.3″ (694 mm) -2.7%
265/35R20 27.3″ (694 mm) -2.7%
265/40R19 27.4″ (695 mm) -2.5%
235/45R19 27.4″ (695 mm) -2.5%
325/25R21 27.4″ (695 mm) -2.5%
235/40R20 27.4″ (696 mm) -2.4%
145/65R20 27.4″ (696 mm) -2.4%
355/30R19 27.4″ (697 mm) -2.2%
305/35R19 27.4″ (697 mm) -2.2%
235/35R21 27.4″ (697 mm) -2.2%
315/30R20 27.5″ (698 mm) -2.1%
275/30R21 27.5″ (699 mm) -2%
175/55R20 27.6″ (700 mm) -1.8%
275/35R20 27.6″ (700 mm) -1.8%
155/70R19 27.6″ (701 mm) -1.7%
215/45R20 27.6″ (702 mm) -1.5%
275/40R19 27.7″ (703 mm) -1.4%
315/35R19 27.7″ (703 mm) -1.4%
245/45R19 27.7″ (703 mm) -1.4%
245/40R20 27.7″ (704 mm) -1.3%
195/50R20 27.7″ (704 mm) -1.3%
325/30R20 27.7″ (704 mm) -1.3%
245/35R21 27.8″ (705 mm) -1.1%
285/30R21 27.8″ (705 mm) -1.1%
165/60R20 27.8″ (706 mm) -1%
285/35R20 27.9″ (708 mm) -0.7%
155/65R20 28″ (710 mm) -0.4%
335/30R20 28″ (710 mm) -0.4%
225/45R20 28″ (710 mm) -0.4%
255/35R21 28″ (711 mm) -0.3%
285/40R19 28″ (711 mm) -0.3%
295/30R21 28″ (711 mm) -0.3%
355/25R21 28″ (711 mm) -0.3%
255/40R20 28″ (712 mm) -0.1%
295/35R20 28.1″ (714 mm) 0.1%
145/80R19 28.1″ (715 mm) 0.3%
345/30R20 28.2″ (716 mm) 0.4%
305/30R21 28.2″ (717 mm) 0.6%
235/50R19 28.3″ (719 mm) 0.8%
295/40R19 28.3″ (719 mm) 0.8%
265/35R21 28.3″ (719 mm) 0.8%
235/45R20 28.3″ (720 mm) 1%
265/40R20 28.3″ (720 mm) 1%
265/45R19 28.4″ (721 mm) 1.1%
305/35R20 28.4″ (722 mm) 1.3%
315/30R21 28.5″ (723 mm) 1.4%
275/35R21 28.5″ (725 mm) 1.7%
345/35R19 28.5″ (725 mm) 1.7%
275/40R20 28.7″ (728 mm) 2.1%
245/45R20 28.7″ (728 mm) 2.1%
315/35R20 28.7″ (728 mm) 2.1%
325/30R21 28.7″ (729 mm) 2.2%
245/50R19 28.7″ (729 mm) 2.2%
245/40R21 28.7″ (729 mm) 2.2%
275/45R19 28.8″ (731 mm) 2.5%
225/55R19 28.8″ (731 mm) 2.5%
155/80R19 28.8″ (731 mm) 2.5%
285/35R21 28.9″ (733 mm) 2.8%

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