# 275/65r20 vs 285/55r20 Tire Size

When you’re looking to buy new tires, you first need to decide what size you need. After that, it’s a matter of choosing which type of tire is right for your car. Both have pros and cons, but in general, they have some essential differences.

Not only do they have different measurements, but they also operate differently once they are installed on your vehicle. Which one should you choose? Here’s what you need to know about these two different options for the size of your car’s tires.

## 275 65r20 vs 285 55r20 Table

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### What Does 275 65r20 Tire Mean?

The 275 65r20 tire size is a metric tire. The first number, “275,” is the tire’s width in millimeters. The second number, “65,” is the aspect ratio. This percentage corresponds to the height of the sidewall.

In this case, it would be 65% of 275 mm. The “r” in this case stands for radial, which is the type of tire. The last number, “20,” is the diameter of the wheel in inches.

Tire Diameter
The height of the tire can help you to understand the diameter of the tire. To calculate the tire’s diameter, you must take its width and multiply it by the aspect ratio. The diameter of the 275 65r20 tire size would be 865.5 mm. This is equivalent to 34.07 inches.

The diameter of the 285 55r20 tire size would be 821.5 mm. This is equivalent to 32.34 inches. The difference between those tires is 1.73 inches or 5.1%. As you can see, the difference in diameter is not huge, but it is still essential to know the difference.

Section Width
The section width of a tire is the width of the tire measured in millimeters. The section width of the 275 65r20 tire size is 275 mm. The section width of the 285 55r20 tire size is 285 mm. As you can see, the section width of the 285 55r20 tire size is slightly wider than the 275 65r20 tire size.

The difference between these two tires is only ten millimeters. To put that into perspective, the average width of human hair is about 70 micrometers. This means that the difference between these two tires is about 142 times wider than human hair.

Circumference
The circumference of a tire is the distance around the outside of the tire. The circumference of the 275 65r20 tire size would be 2719.05 mm. This is equivalent to 107.05 inches. The circumference of the 285 55r20 tire size would be 2580.82 mm.

This is equivalent to 101.61 inches. The difference between those two tires is 5.44 inches or 5.1%. As you can see, the difference in circumference is significant. This is because the diameter of the tire is different.

Revolutions Per Mile
The revolutions per mile (RPM) is the number of times that the tire will go around in one mile. The RPM of the 275 65r20 tire size would be 591. The RPM of the 285 55r20 tire size would be 623. As you can see, the 285 55r20 tire size has a higher RPM than the 275 65r20 tire size. The difference between the two tire sizes is 32 RPM.

Sidewall Height
The sidewall height of a tire is the distance from the edge of the wheel to the top of the tire. The sidewall height of the 275 65r20 tire size would be 178.75 mm. The sidewall height of the 285 55r20 tire size would be 156.75 mm.

As you can see, the sidewall height of the 275 65r20 tire size is slightly shorter than the 285 55r20 tire size. The difference between these two tires is 22 mm.

Wheel Size
The wheel size of a tire is the diameter of the wheel that the tire is meant to be used with. The wheel size of the 275 65r20 tire size would be 20 inches. The wheel size of the 285 55r20 tire size would also be 20 inches. As you can see, the two tire sizes are meant to be used with the same size wheel.

Construction Type
The construction type of a tire is the way that the tire is made. The 275 65r20 tire size is a radial tire. The 285 55r20 tire size is also a radial tire. As you can see, the construction type of the two tire sizes is the same. Radial tires are the most common type of tire. They are made with layers of cord that run from the bead to the tread in a radial direction. This gives the tire strength in all directions.

Suitable Vehicle
The 275/65R20 tire size is standard on pickup trucks such as the Chevrolet Silverado 3500 HD, Ford F-250 Super Duty, and GMC Sierra 2500 HD. As these vehicles are used both on and off road, a larger 285/55R20 tire size may be more beneficial.

The 255/70R18 tire size is commonly found on Toyota Tundras but offers limited benefits in comparison to the other two options mentioned.

Our Observation
The sidewall height is the main difference between 275 65r20 and 285 55r20 tire sizes. The 275 65r20 tire size is 0.87 inch or 12.3% taller than 285 55r20 tire size. Also, if you check the section width, the 285 55r20 tire size is 0.39 inches or 3.6% wider than the 275 65r20 tire size.