Tire Size 285/55r20 vs 305/55r20
The tire size 305/55R20 is equal to 33.2 inches in overall diameter and 12 inches in tread width, designed to fit a 20-inch rim. In comparison, the tire size 285/55R20 measures 32.4 inches in overall diameter and 11.2 inches in tread width, also designed to fit a 20-inch rim.
285/55r20 vs 305/55r20 Table
It’s no secret that choosing the right set of tires is essential for both safety and performance. We will compare the 285 55r20 and 305 55r20 tire sizes to help you make the best decision for your needs.
| Feature | 285/55r20 | 305/55r20 | Difference |
|---|---|---|---|
| Diameter | 32.34″ | 33.21″ | 0.87 inch |
| Width | 11.22″ | 12.01″ | 0.79 inch |
| Circum. | 101.61″ | 104.33″ | 2.72 inch |
| Sidewall Height | 6.17″ | 6.6′ | 0.43 inch |
| Revolutions | 623.58 | 607.31 | 16.26 |
Alternative Tire Size For 285/55r20
This table showing the overall diameter and percentage difference for various tire sizes that can be used as alternatives to the tire size 285/55R20.
| Tire Size | Overall Diameter | Difference |
|---|---|---|
| 285/55R20 | 32.4″ (822 mm) | -2.6% |
| 315/50R20 | 32.4″ (824 mm) | -2.4% |
| 265/60R20 | 32.5″ (826 mm) | -2.1% |
| 295/55R20 | 32.8″ (832 mm) | -1.4% |
| 325/50R20 | 32.8″ (834 mm) | -1.2% |
| 275/60R20 | 33″ (838 mm) | -0.7% |
| 375/45R20 | 33.3″ (846 mm) | 0.2% |
| 285/60R20 | 33.5″ (850 mm) | 0.7% |
| 275/55R22 | 33.9″ (861 mm) | 2.0% |
| 295/60R20 | 33.9″ (862 mm) | 2.1% |
| 355/50R20 | 34″ (864 mm) | 2.4% |
| 275/65R20 | 34.1″ (866 mm) | 2.6% |
Alternative Tire Size For 285/55r20
It is important to note that any replacement tires must be within 3% of the original tire’s overall diameter to ensure proper fit and performance.
| Tire Size | Overall Diameter | Difference |
|---|---|---|
| 245/60R20 | 31.6″ (802 mm) | -2.4% |
| 295/50R20 | 31.7″ (804 mm) | -2.2% |
| 275/55R20 | 31.9″ (810 mm) | -1.5% |
| 255/60R20 | 32″ (814 mm) | -1.0% |
| 305/50R20 | 32″ (814 mm) | -1.0% |
| 315/50R20 | 32.4″ (824 mm) | 0.2% |
| 265/60R20 | 32.5″ (826 mm) | 0.5% |
| 295/55R20 | 32.8″ (832 mm) | 1.2% |
| 325/50R20 | 32.8″ (834 mm) | 1.5% |
| 275/60R20 | 33″ (838 mm) | 1.9% |
| 305/55R20 | 33.2″ (844 mm) | 2.7% |
| 375/45R20 | 33.3″ (846 mm) | 2.9% |
Tire Width
The width of the 285 55r20 tire is 285 millimeters. The width of the 305 55r20 tire is 305 millimeters. That means that the 305-millimeter tire is 20 millimeters wider than the 285-millimeter tire. Wider tires typically offer better traction and stability. Still, they can also be more challenging to handle, especially at high speeds.
Aspect Ratio
The aspect ratio of a tire is the sidewall height as a percentage of the width. The sidewall height is also known as the “profile.” In this case, we’re looking at the 55-series tires. That means that the sidewall height of both tires is 55% of their respective widths.
The 285 55r20 tire has a sidewall height of 156.75 millimeters. The 305 55r20 tire has a sidewall height of 167.75 millimeters. That means that the 305-millimeter tire is taller by just about ten millimeters. Taller tires can offer a smoother ride, but they may also decrease fuel efficiency and increase braking distances.
Construction Type
Both the 285 55r20 and 305 55r20 tires are radial. Radial tires are designed with steel belts that run across the tread in a radial direction (from the center of the tire to the edge). This design offers several advantages, including better fuel efficiency, longer tread life, and increased stability.
Rim Size
The final aspect of tire size that we’ll be looking at is the rim size. The 285 55r20 and 305 55r20 tires are designed to fit a 20-inch diameter wheel. That’s the most common size for SUVs and trucks.
Circumference
The circumference of a tire is the distance around the outside of the tire. It’s important to know the circumference of your tires because it can affect speedometers, odometers, and fuel economy.
The circumference of the 285 55r20 tire is about 101.61 inches. The circumference of the 305 55r20 tire is about 104.33 inches. That means that the 305-millimeter tire is about three and a half inches longer than the 285-millimeter tire.
Revolutions Per Mile
The number of revolutions per mile (RPM) is a measure of how often the tire turns as it goes one mile. The higher the number, the more times the tire will turn in a mile. The RPM of the 285 55r20 tire is about 623. The RPM of the 305 55r20 tire is about 607. That means that the 305-millimeter tire will turn about 16 times fewer in a mile than the 285-millimeter tire.
Generally speaking, smaller tires have higher RPMs, and larger tires have lower RPMs. That’s because it takes more effort to turn a larger tire than a smaller one.
Our Observation
Based on our comparison, the 305/55r20 tire size provides a wider tread, taller sidewall, and larger overall diameter, making it a good choice for off-road driving and uneven terrain. The 285/55r20 tire size has a smaller overall diameter, which may improve acceleration and fuel efficiency, and a slightly narrower tread width, which may provide better handling on smooth, paved roads.
Ultimately, the best tire size for you will depend on your driving needs and preferences. If you spend a lot of time off-roading or driving on uneven terrain, the 305/55r20 tire size may be the better option. On the other hand, if you primarily drive on paved roads and prioritize fuel efficiency and acceleration, the 285/55r20 tire size may be the way to go.
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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.
