155R12C Tire Size in Inches & Millimeters

Tire size “155/R12C” 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 155R12C to inches, you must know what these numbers represent.

So let us know 155R12C in simple words:

First number “155” indicates the tire’s width in millimeters.
Second number “” refers to the aspect ratio, which is the height of the tire’s sidewall as a percentage of its width.
Third number “R12C” refers to a tire that is designed to fit a 12-inch diameter rim.

Therefore, when converting the tire size 155R12C to inches, it can be concluded that the width of the tire will be approximately 6.1 inches ( 155 mm= 6.1 in), and the sidewall height will be approximately 4.9 inches (% of 6.1 inches = 4.9 inches).

How to convert 155R12C into Inches (imperial)?

To convert tire size 155R12C to inches (Imperial) –

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

  • 155 millimeters/25.4 = approximately 6.1 inches
    So, the width of the tire is approximately 6.1 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 = 6.1 inches * /100 = approximately 4.9 inches
    So, the tire sidewall height is approximately 4.9 inches.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number “12” indicates the rim diameter in inches. In this case, it’s already in inches.
So, the converted tire size “155R12C” in inches (imperial) is approximately:

  • Width: 6.1 inches
  • Sidewall Height: 4.9 inches
  • Rim Diameter: 12 inches

How to convert 155R12C into Millimeters (metric)?

To convert the tire size 155R12C into millimeters (metric) –

1. Width Conversion: The first number in the tire size, “155“, represents the tire’s width in millimeters. Since it’s already in millimeters, there’s no need for conversion.

  • Width: 155millimeters

2. Aspect Ratio Calculation: The second number “” 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 = 155 millimeters * / 100 = 124 mm millimeters
    So, the tire’s sidewall height is approximately 124 mm millimeters.

3. Rim Diameter: The “R” in the tire size stands for “radial construction” and the last number, “12” 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 = 12 inches * 25.4 millimeters per inch = 305 mm millimeters
    So, the rim diameter is approximately 305 mm millimeters.

So, the converted tire size “155R12C” in millimeters (metric) is approximately:

  • Width: 155 mm
  • Sidewall Height: 124 mm
  • Rim Diameter: 305 mm

Alternate Tire Size of 155R12C For replacement

Tire Size Overall Diameter Difference
165/70R12 21.1″ (537 mm) -2.9%
145/80R12 21.1″ (537 mm) -2.9%
145R12 21.1″ (537 mm) -2.9%
165/55R14 21.2″ (538 mm) -2.7%
175/60R13 21.3″ (540 mm) -2.4%
205/45R14 21.3″ (540 mm) -2.4%
185/50R14 21.3″ (542 mm) -2%
145/65R14 21.4″ (544 mm) -1.6%
165/65R13 21.4″ (544 mm) -1.6%
195/55R13 21.4″ (544 mm) -1.6%
215/50R13 21.5″ (546 mm) -1.3%
135/80R13 21.5″ (546 mm) -1.3%
155/70R13 21.6″ (548 mm) -0.9%
185/60R13 21.7″ (552 mm) -0.2%
155/80R12 21.8″ (553 mm) 0%
165/60R14 21.8″ (554 mm) 0.2%
225/50R13 21.9″ (556 mm) 0.5%
225/45R14 22″ (558 mm) 0.9%
155/65R14 22″ (558 mm) 0.9%
175/65R13 22″ (558 mm) 0.9%
185/55R14 22″ (560 mm) 1.3%
145/80R13 22.1″ (562 mm) 1.6%
205/50R14 22.1″ (562 mm) 1.6%
165/70R13 22.1″ (562 mm) 1.6%
195/60R13 22.2″ (564 mm) 2%
175/60R14 22.3″ (566 mm) 2.4%
235/50R13 22.3″ (566 mm) 2.4%

Leave a Comment