37×12.50r20 in Metric
The maze of numbers and letters on the sidewalls can be daunting. Particularly when transitioning between imperial and metric measurements, the confusion amplifies.
One common query among off-road enthusiasts and truck owners is finding the closest metric equivalent to the 37×12.50R20 tire size. So, what does this size actually mean, and how can you find its metric counterpart?
Reading Tire Size
To demystify the imperial tire size 37×12.50R20, let’s break it down:
- 37: This number represents the overall diameter of the tire in inches. So, the tire is 37 inches tall from the ground to the top of the tire.
- 12.50: This is the tire’s width in inches. It means the tire is 12.5 inches wide from sidewall to sidewall.
- R: Stands for radial construction, indicating the tire’s internal construction type.
- 20: This is the rim diameter in inches, signifying the size of the wheel the tire is designed to fit.
Understanding these components is crucial for finding a suitable metric equivalent, ensuring that the new tires will fit your vehicle without any issues.
Closest Metric Equivalent
Converting the imperial size to a metric one involves a bit of math, but it’s straightforward once you grasp the basics. Here’s how we determine the closest metric equivalent:
- Convert the Width: The imperial width is 12.50 inches. To convert inches to millimeters (the standard unit for tire width in metric sizes), multiply by 25.4 (since 1 inch equals 25.4 millimeters). 12.50 inches×25.4=317.5 mmSo, the width is approximately 318 mm.
- Determine the Aspect Ratio: This is where it gets a bit tricky. The aspect ratio in metric sizes is the height of the tire’s sidewall expressed as a percentage of its width. We need an aspect ratio that, when calculated, gives us a total diameter close to 37 inches.
- Calculate the Overall Diameter: The formula for the overall diameter in metric sizes is: Overall Diameter=(2×Section Height)+Rim DiameterWhere:
- Section Height = Width × (Aspect Ratio ÷ 100)
- Rim Diameter is converted to inches (since 20 inches is already in inches, we can use it directly).
After testing several combinations, the 315/70R20 metric size emerges as the closest match:
- Width: 315 mm (approximately 12.4 inches, very close to the 12.5-inch width)
- Aspect Ratio: 70%
- Section Height: 315 mm×70%=220.5 mm
- Section Height in inches: 220.5 mm÷25.4=8.677 inches
- Overall Diameter: (2×8.677 inches)+20 inches=37.354 inches
The calculated overall diameter is approximately 37.35 inches, which is remarkably close to the original 37-inch tire.
The slight difference is negligible and won’t significantly affect the vehicle’s performance or speedometer readings.
Alternatives to This Size
While the 315/70R20 is the closest metric equivalent, there are alternative sizes that might suit different preferences or requirements. Here’s a list of alternatives with their overall diameters and how they differ from the original size:
| Tire Size | Overall Diameter | Difference % |
|---|---|---|
| 37×12.50R20 | 37.00 | 0.00% |
| 36×12.50R20 | 36.00 | -2.70% |
| 315/45R24 | 36.27 | -1.97% |
| 315/50R24 | 37.68 | 1.84% |
| 325/55R22 | 35.95 | -2.84% |
| 36×12.50R15 | 36.00 | -2.70% |
| 36×12.50R17 | 36.00 | -2.70% |
| 37×12.50R15 | 37.00 | 0.00% |
| 37×12.50R16.5 | 37.00 | 0.00% |
| 37×12.50R16 | 37.00 | 0.00% |
| 37×12.50R17 | 37.00 | 0.00% |
| 37×12.50R18 | 37.00 | 0.00% |
| 37×12.50R22 | 37.00 | 0.00% |
| 37x13R15 | 37.00 | 0.00% |
| 38×12.50R15 | 38.00 | 2.70% |
| 38×12.50R17 | 38.00 | 2.70% |
| 38x13R15 | 38.00 | 2.70% |
| 37×12.50R17 | 37.00 | 0.00% |
Note: The diameter difference is calculated based on the original 37×12.50R20 size. These alternatives offer various options depending on the wheel size and desired tire characteristics.
For instance, opting for a 36-inch tire might slightly lower your vehicle, potentially improving handling but reducing ground clearance. Conversely, a 38-inch tire increases ground clearance but may affect fuel efficiency and require vehicle modifications.
37×12.50R20 Equivalent
The closest metric equivalent to the 37×12.50R20 tire size is the 315/70R20. This metric size mirrors the imperial dimensions closely, offering a similar overall diameter and width.
The 315mm width and 70% aspect ratio combine to produce a tire that maintains the performance characteristics of the original size.
How Tall is a 37×12.50R20 Tire?
A 37×12.50R20 tire is 37 inches tall. This measurement refers to the tire’s overall diameter, which is the distance from the ground to the top of the tire when mounted and properly inflated. This substantial height is common in off-road and heavy-duty applications, providing increased ground clearance.
How Wide is a 37×12.50R20 Tire?
The tire is 12.50 inches wide, measured from one sidewall to the other at the widest point. This width offers a broad contact patch with the road or trail surface, enhancing traction and stability, especially in off-road conditions where wider tires can better distribute the vehicle’s weight.
What Size Rim Fits a 37×12.50R20?
A 37×12.50R20 tire is designed to fit a 20-inch rim. The “20” in the tire size denotes the wheel diameter the tire is intended for. It’s crucial to match the tire with the correct rim size to ensure proper fitment, safety, and performance.
Our Observation
Choosing the right tire size is more than just matching numbers; it’s about understanding how dimensions affect your vehicle’s performance and handling.
The 315/70R20 stands out as the closest metric equivalent to the 37×12.50R20, providing a seamless transition between measurement systems. This size maintains the essential characteristics—overall diameter and width—ensuring that speedometer readings remain accurate and that the vehicle’s stance and ground clearance are preserved.
However, it’s important to consider factors such as tire availability, tread patterns, and load ratings. While the size might match, different tire models can vary in construction and performance.
Always consult with a tire professional to ensure compatibility with your vehicle’s specifications and to address any potential need for adjustments, such as recalibrating speedometers or modifying suspension components.
In exploring alternatives, we found that options like the 315/45R24 and 315/50R24 offer slight variations in diameter but require larger rims, which may not be suitable for all vehicles.
Similarly, sizes like 38×12.50R15 increase the overall diameter, potentially necessitating vehicle modifications to accommodate the larger size.
Caitlin McCormack is a lead writer at Tiresizecompare.com and a trusted guide at AmarCalculator. With an extensive background in finance and mathematics, she simplifies complex calculations and delivers precise insights. Caitlin’s expertise ensures readers receive accurate and reliable information to make informed decisions. Her passion for numbers and dedication to clarity make her an invaluable resource for tire comparisons.
