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255/45R20 Tire Size
All You Need to Know About 255/45R20 Tires
255/45R20 tires have a section width of 255 millimeters (mm), an aspect ratio of 45%, radial construction, and a 20-inch wheel diameter. This size is commonly found on mid-size and full-size SUVs, sporty crossovers, and performance-oriented sedans, where a balance between road comfort, stability, and responsive handling is desired. Before choosing 255/45R20 tires, converting the measurements into inches and comparing them with similar sizes such as 245/45R20 and 235/60R18 helps ensure proper fitment without unwanted changes to ride height, clearance, or vehicle calibration.
What Are the Dimensions of a 255/45R20 Tire in Inches?
A 255/45R20 tire has a section width of 10.04 inches (≈ 10.0") and a sidewall height of 4.52 inches (≈ 4.5"). The overall diameter of a 255/45R20 tire is 29.04 inches (≈ 29.0"), and the circumference is approximately 91.21 inches (≈ 91.2"). The recommended rim width range for the 255/45R20 size is typically 8.0 to 9.5 inches. In inches, 255/45R20 can be represented as 29.04" × 10.04" R20.
How tall and wide are 255/45R20 tires?
A 255/45R20 tire is approximately 29.04 inches (737.50 mm) tall and 10.04 inches (255 mm) wide.
Recommended 255/45R20 Tires
Well-regarded options in 255/45R20 size include:
Comparison of 255/45R20 With Similar Tire Sizes
Comparing 255/45R20 with 245/45R20 and 235/60R18 highlights how small changes in width, aspect ratio, and wheel diameter affect ride height, comfort, and interchangeability.
What Is the Difference Between 255/45R20 vs 245/45R20?
The main difference between 255/45R20 and 245/45R20 is the section width. Both tires fit 20-inch wheels and share the same aspect ratio, but the wider 255 tire has a slightly taller sidewall and a larger overall diameter.
The 255/45R20 has a sidewall height of 114.75 mm (≈ 4.52") and an overall diameter of 737.50 mm (≈ 29.04"). The 245/45R20 has a sidewall height of 110.25 mm (≈ 4.34") and an overall diameter of 728.50 mm (≈ 28.68").
This means the 255/45R20 is 10 mm wider, has a 4.50 mm (≈ 0.18") taller sidewall, and is 9.00 mm (≈ 0.35") larger overall.
255/45R20 vs 245/45R20 Tire Size Comparison Table
Tire Dimension | 255/45R20 (mm & in) | 245/45R20 (mm & in) | Difference between 255/45R20 / 245/45R20 (mm & in) | Percentage Difference between 255/45R20 / 245/45R20 |
Section Width | 255 mm (≈ 10.04") | 245 mm (≈ 9.65") | 10 mm (≈ 0.39") | ≈ 4.08% |
Sidewall Height | 114.75 mm (≈ 4.52") | 110.25 mm (≈ 4.34") | 4.50 mm (≈ 0.18") | ≈ 4.08% |
Overall Diameter | 737.50 mm (≈ 29.04") | 728.50 mm (≈ 28.68") | 9.00 mm (≈ 0.35") | ≈ 1.24% |
Circumference | 2316.6 mm (≈ 91.21") | 2288.7 mm (≈ 90.10") | 27.9 mm (≈ 1.10") | ≈ 1.24% |
Radius | 368.75 mm (≈ 14.52") | 364.25 mm (≈ 14.34") | 4.50 mm (≈ 0.18") | ≈ 1.24% |
Rim Diameter | 20" | 20" | — | 0% |
Recommended Rim Width | 8.0-9.5" | 7.5-9.0" | — | — |
Can I use 245/45R20 instead of 255/45R20?
Yes, in most cases. The overall diameter difference of ≈ 1.2% is well within the commonly accepted tolerance, so speedometer accuracy and vehicle calibration remain close to stock. The main consideration is width: the narrower 245/45R20 may slightly reduce grip and fill the wheel well less. A 255mm tire offers slightly more "bulge" to protect your rim from curbs. Moving to a 245mm tire on the same rim may leave the edge of the wheel slightly more exposed.
If your vehicle is AWD, you must replace all four tires at once. Mixing a 245/45R20 on the front and a 255/45R20 on the rear can damage your center differential because the tires will be spinning at different speeds.
What Is the Difference Between 255/45R20 vs 235/60R18?
The main differences between 255/45R20 and 235/60R18 are the section width, aspect ratio, and rim diameter. The 255/45R20 fits a 20-inch wheel, while the 235/60R18 fits an 18-inch wheel, making these sizes not directly interchangeable without changing wheels.
The 255/45R20 has a sidewall height of 114.75 mm (≈ 4.52") and an overall diameter of 737.50 mm (≈ 29.04"). The 235/60R18 has a sidewall height of 141.00 mm (≈ 5.55") and an overall diameter of 739.20 mm (≈ 29.11").
This means the 235/60R18 is 20 mm narrower, has a 26.25 mm (≈ 1.03") taller sidewall, and is only 1.70 mm (≈ 0.07") larger overall.
255/45R20 vs 235/60R18 Tire Size Comparison Table
Tire Dimension | 255/45R20 (mm & in) | 235/60R18 (mm & in) | Difference between 255/45R20 / 235/60R18 (mm & in) | Percentage Difference between 255/45R20 / 235/60R18 |
Section Width | 255 mm (≈ 10.04") | 235 mm (≈ 9.25") | 20 mm (≈ 0.79") | ≈ 8.51% |
Sidewall Height | 114.75 mm (≈ 4.52") | 141.00 mm (≈ 5.55") | 26.25 mm (≈ 1.03") | ≈ 22.88% |
Overall Diameter | 737.50 mm (≈ 29.04") | 739.20 mm (≈ 29.11") | 1.70 mm (≈ 0.07") | ≈ 0.23% |
Circumference | 2316.6 mm (≈ 91.21") | 2321.9 mm (≈ 91.42") | 5.3 mm (≈ 0.21") | ≈ 0.23% |
Radius | 368.75 mm (≈ 14.52") | 369.60 mm (≈ 14.55") | 0.85 mm (≈ 0.03") | ≈ 0.23% |
Rim Diameter | 20" | 18" | — | — |
Recommended Rim Width | 8.0-9.5" | 6.5-8.5" | — | — |
Can I use 235/60R18 instead of 255/45R20?
No. A 235/60R18 tire cannot be mounted on a 20-inch wheel, so it is not interchangeable with a 255/45R20 without changing wheels. Switching to this size requires purchasing 18-inch wheels, which is a mandatory hardware change.
If the correct 18-inch wheels are installed, the overall diameter difference is only ≈ 0.23%, meaning speedometer accuracy and vehicle calibration remain essentially unchanged. The 1.03-inch increase in sidewall with the 235/60R18 is significant. This extra "rubber cushion" acts as a secondary shock absorber, making the car much smoother over potholes and expansion joints. Taller sidewalls provide better protection for your rims against "curb rash" and pinch flats.
The trade-off with 235/60R18 instead of 255/45R20 is "steering mushiness." Because the sidewall is taller and more flexible, the car won't feel as "darty" or sharp when you turn the steering wheel quickly.
All You Need to Know About 255/45R20 Tires
255/45R20 tires have a section width of 255 millimeters (mm), an aspect ratio of 45%, radial construction, and a 20-inch wheel diameter. This size is commonly found on mid-size and full-size SUVs, sporty crossovers, and performance-oriented sedans, where a balance between road comfort, stability, and responsive handling is desired. Before choosing 255/45R20 tires, converting the measurements into inches and comparing them with similar sizes such as 245/45R20 and 235/60R18 helps ensure proper fitment without unwanted changes to ride height, clearance, or vehicle calibration.
What Are the Dimensions of a 255/45R20 Tire in Inches?
A 255/45R20 tire has a section width of 10.04 inches (≈ 10.0") and a sidewall height of 4.52 inches (≈ 4.5"). The overall diameter of a 255/45R20 tire is 29.04 inches (≈ 29.0"), and the circumference is approximately 91.21 inches (≈ 91.2"). The recommended rim width range for the 255/45R20 size is typically 8.0 to 9.5 inches. In inches, 255/45R20 can be represented as 29.04" × 10.04" R20.
How tall and wide are 255/45R20 tires?
A 255/45R20 tire is approximately 29.04 inches (737.50 mm) tall and 10.04 inches (255 mm) wide.
Recommended 255/45R20 Tires
Well-regarded options in 255/45R20 size include:
Comparison of 255/45R20 With Similar Tire Sizes
Comparing 255/45R20 with 245/45R20 and 235/60R18 highlights how small changes in width, aspect ratio, and wheel diameter affect ride height, comfort, and interchangeability.
What Is the Difference Between 255/45R20 vs 245/45R20?
The main difference between 255/45R20 and 245/45R20 is the section width. Both tires fit 20-inch wheels and share the same aspect ratio, but the wider 255 tire has a slightly taller sidewall and a larger overall diameter.
The 255/45R20 has a sidewall height of 114.75 mm (≈ 4.52") and an overall diameter of 737.50 mm (≈ 29.04"). The 245/45R20 has a sidewall height of 110.25 mm (≈ 4.34") and an overall diameter of 728.50 mm (≈ 28.68").
This means the 255/45R20 is 10 mm wider, has a 4.50 mm (≈ 0.18") taller sidewall, and is 9.00 mm (≈ 0.35") larger overall.
255/45R20 vs 245/45R20 Tire Size Comparison Table
Tire Dimension | 255/45R20 (mm & in) | 245/45R20 (mm & in) | Difference between 255/45R20 / 245/45R20 (mm & in) | Percentage Difference between 255/45R20 / 245/45R20 |
Section Width | 255 mm (≈ 10.04") | 245 mm (≈ 9.65") | 10 mm (≈ 0.39") | ≈ 4.08% |
Sidewall Height | 114.75 mm (≈ 4.52") | 110.25 mm (≈ 4.34") | 4.50 mm (≈ 0.18") | ≈ 4.08% |
Overall Diameter | 737.50 mm (≈ 29.04") | 728.50 mm (≈ 28.68") | 9.00 mm (≈ 0.35") | ≈ 1.24% |
Circumference | 2316.6 mm (≈ 91.21") | 2288.7 mm (≈ 90.10") | 27.9 mm (≈ 1.10") | ≈ 1.24% |
Radius | 368.75 mm (≈ 14.52") | 364.25 mm (≈ 14.34") | 4.50 mm (≈ 0.18") | ≈ 1.24% |
Rim Diameter | 20" | 20" | — | 0% |
Recommended Rim Width | 8.0-9.5" | 7.5-9.0" | — | — |
Can I use 245/45R20 instead of 255/45R20?
Yes, in most cases. The overall diameter difference of ≈ 1.2% is well within the commonly accepted tolerance, so speedometer accuracy and vehicle calibration remain close to stock. The main consideration is width: the narrower 245/45R20 may slightly reduce grip and fill the wheel well less. A 255mm tire offers slightly more "bulge" to protect your rim from curbs. Moving to a 245mm tire on the same rim may leave the edge of the wheel slightly more exposed.
If your vehicle is AWD, you must replace all four tires at once. Mixing a 245/45R20 on the front and a 255/45R20 on the rear can damage your center differential because the tires will be spinning at different speeds.
What Is the Difference Between 255/45R20 vs 235/60R18?
The main differences between 255/45R20 and 235/60R18 are the section width, aspect ratio, and rim diameter. The 255/45R20 fits a 20-inch wheel, while the 235/60R18 fits an 18-inch wheel, making these sizes not directly interchangeable without changing wheels.
The 255/45R20 has a sidewall height of 114.75 mm (≈ 4.52") and an overall diameter of 737.50 mm (≈ 29.04"). The 235/60R18 has a sidewall height of 141.00 mm (≈ 5.55") and an overall diameter of 739.20 mm (≈ 29.11").
This means the 235/60R18 is 20 mm narrower, has a 26.25 mm (≈ 1.03") taller sidewall, and is only 1.70 mm (≈ 0.07") larger overall.
255/45R20 vs 235/60R18 Tire Size Comparison Table
Tire Dimension | 255/45R20 (mm & in) | 235/60R18 (mm & in) | Difference between 255/45R20 / 235/60R18 (mm & in) | Percentage Difference between 255/45R20 / 235/60R18 |
Section Width | 255 mm (≈ 10.04") | 235 mm (≈ 9.25") | 20 mm (≈ 0.79") | ≈ 8.51% |
Sidewall Height | 114.75 mm (≈ 4.52") | 141.00 mm (≈ 5.55") | 26.25 mm (≈ 1.03") | ≈ 22.88% |
Overall Diameter | 737.50 mm (≈ 29.04") | 739.20 mm (≈ 29.11") | 1.70 mm (≈ 0.07") | ≈ 0.23% |
Circumference | 2316.6 mm (≈ 91.21") | 2321.9 mm (≈ 91.42") | 5.3 mm (≈ 0.21") | ≈ 0.23% |
Radius | 368.75 mm (≈ 14.52") | 369.60 mm (≈ 14.55") | 0.85 mm (≈ 0.03") | ≈ 0.23% |
Rim Diameter | 20" | 18" | — | — |
Recommended Rim Width | 8.0-9.5" | 6.5-8.5" | — | — |
Can I use 235/60R18 instead of 255/45R20?
No. A 235/60R18 tire cannot be mounted on a 20-inch wheel, so it is not interchangeable with a 255/45R20 without changing wheels. Switching to this size requires purchasing 18-inch wheels, which is a mandatory hardware change.
If the correct 18-inch wheels are installed, the overall diameter difference is only ≈ 0.23%, meaning speedometer accuracy and vehicle calibration remain essentially unchanged. The 1.03-inch increase in sidewall with the 235/60R18 is significant. This extra "rubber cushion" acts as a secondary shock absorber, making the car much smoother over potholes and expansion joints. Taller sidewalls provide better protection for your rims against "curb rash" and pinch flats.
The trade-off with 235/60R18 instead of 255/45R20 is "steering mushiness." Because the sidewall is taller and more flexible, the car won't feel as "darty" or sharp when you turn the steering wheel quickly.
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