Tire Size 33×12.5r20 in Metric

The 33×12.5R20 tire size translates to 318/52R15 in metric terms. However, standard metric sizes typically round to the nearest 5 or 10 mm for width and 5 for aspect ratio, making 315/50R20 the closest practical equivalent.

33×12.50r20 in inches

This table provides a breakdown of the 33×12.50R20 tire size in inches, helping you to better understand its features and metrics.

Understanding Tire Sizing

Tire sizes can be confusing, especially when switching between inch-based and metric systems. To clarify, a tire size like 33×12.5R20 provides three main pieces of information:

• 33 inches: This is the overall tire height (or diameter) when fully inflated.
• 12.5 inches: This is the section width, which measures the width of the tire from sidewall to sidewall.
• R20: This indicates the tire is radial and has a 20-inch rim diameter.

Converting these measurements into a metric format follows a systematic approach, which involves converting inches to millimeters and calculating the aspect ratio.

33×12.5R20 to Metric

Converting 33×12.5R20 tire size to its metric equivalent for international compatibility and understanding.

Convert Section Width

The section width of the tire is 12.5 inches. To convert inches to millimeters, multiply the inch measurement by 25.4 (since 1 inch equals 25.4 millimeters).

• Section width = 12.5″ × 25.4 Section width = 317.5 mm

In tire sizing, this is typically rounded to the nearest 5 or 10 millimeters, so the section width would be considered 315 mm.

Calculate Sidewall Height

The sidewall height is the difference between the overall tire height (33 inches) and the rim diameter (20 inches), divided by 2. This gives you the height of the tire sidewall.

• Sidewall height = (33″ – 20″) ÷ 2 Sidewall height = 13″ ÷ 2 Sidewall height = 6.5″

Convert Sidewall Height to Millimeters

To convert the sidewall height into millimeters, multiply the inch measurement by 25.4.

• Sidewall height = 6.5″ × 25.4 Sidewall height = 165.1 mm

Calculate the Aspect Ratio

The aspect ratio is the ratio of the sidewall height to the section width, expressed as a percentage. To find the aspect ratio, divide the sidewall height by the section width and multiply by 100.

• Aspect ratio = (165.1 mm ÷ 317.5 mm) × 100 Aspect ratio ≈ 52%

Since tire aspect ratios are usually rounded to the nearest 5, this would be rounded to 50.

Metric Equivalent of 33×12.5R20

Now that all the key measurements have been calculated, the metric equivalent of the 33×12.5R20 tire size would be approximately 318/52R20. However, when adjusted to match the typical rounding conventions used in tire sizing, the closest standard metric size would be 315/50R20.

Benefits of Converting

Exploring the advantages of using metric tire measurements for global consistency and easier comparisons.

Improved Accuracy

Converting inch-based tire sizes to metric helps improve accuracy in tire selection. The metric system is more precise and widely used in the automotive industry. This can result in better compatibility with various vehicle models, leading to enhanced performance and safety.

Better Compatibility

In many parts of the world, metric tire sizing is the standard. Converting your tire sizes to metric ensures compatibility with international tire standards, making it easier to find replacement tires, especially if you travel or import tires from different regions.

Considerations When Choosing

Key factors to keep in mind when selecting between imperial and metric tire sizes for your vehicle.

Vehicle Fitment

When switching from inch-based to metric tire sizes, it’s crucial to ensure the new tires will fit your vehicle properly. A tire professional can help confirm that the selected metric tire size won’t cause issues with clearance, speedometer accuracy, or handling.

Performance Impacts

Different tire sizes can impact the performance of your vehicle. For example, changing the tire diameter or width can affect acceleration, braking, fuel efficiency, and ride comfort. It’s essential to consider how a switch to a metric tire size might influence these factors.

Common Alternatives

If you’re looking for metric tire sizes close to 33×12.5R20, some common alternatives include:

• 305/55R20: This size offers a slightly narrower section width but maintains a similar overall height, making it a popular choice for trucks and SUVs.
• 325/50R20: With a wider section width and similar height, this option provides a more aggressive stance and enhanced traction for off-road vehicles.

Final Thoughts

Converting tire sizes from inch-based to metric is a useful exercise for anyone looking to match their tires with industry standards or find alternative tire sizes that better fit their vehicle.

The metric equivalent of the 33×12.5R20 tire size is 318/52R20, but the closest standard metric size is 315/50R20. When making the switch, always consider fitment, performance, and compatibility with your vehicle to ensure a safe and optimal driving experience.

• 33×9.5r15 to Metric

Caitlin McCormack

Meet Caitlin McCormack, a Tire Size Expert and Blogger Passionate About Everything Related to Tires. With Years of Experience in the Tire Industry, Caitlin Has Become an Expert in Tire Sizes and Their Impact on Vehicle Performance.