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245/45R20 Tire Size
All You Need to Know About 245/45R20 Tires
245/45R20 tires have a section width of 245 millimeters (mm), an aspect ratio of 45%, radial construction, and a 20-inch wheel diameter. This size is common on sporty sedans, performance-oriented crossovers, and luxury vehicles, where drivers want a responsive feel without going extremely low-profile. Before buying 245/45R20 tires, converting measurements into inches, comparing them with similar sizes such as 245/35R20 and 235/55R18, and understanding interchangeability helps avoid clearance issues, wheel-fitment problems, and unintended changes to speedometer accuracy.
What Are the Dimensions of a 245/45R20 Tire in Inches?
A 245/45R20 tire has a section width of 9.65 inches (≈ 9.6") and a sidewall height of 4.34 inches (≈ 4.3"). The overall diameter of a 245/45R20 tire is 28.68 inches (≈ 28.7"), and the circumference is approximately 90.10 inches (≈ 90.1"). The recommended rim width range for the 245/45R20 size is 7.5 to 9.0 inches.
How tall and wide are 245/45R20 tires?
A 245/45R20 tire is approximately 28.68 inches (728.50 mm) tall and 9.65 inches (245 mm) wide.
Recommended 245/45R20 Tires
Well-regarded options in 245/45R20 include:
Comparison of 245/45R20 With Similar Tire Sizes
Comparing 245/45R20 with 245/35R20 and 235/55R18 shows how changes in aspect ratio and wheel diameter affect overall diameter, ride comfort, handling response, and whether a swap is physically possible without changing wheels.
What Is the Difference Between 245/45R20 vs 245/35R20?
The main difference between 245/45R20 and 245/35R20 is the aspect ratio. Both tires fit 20-inch wheels, but the lower-profile 245/35R20 has a much shorter sidewall and a significantly smaller overall diameter.
The 245/45R20 has a sidewall height of 110.25 mm (≈ 4.34") and an overall diameter of 728.50 mm (≈ 28.68"). The 245/35R20 has a sidewall height of 85.75 mm (≈ 3.38") and an overall diameter of 679.50 mm (≈ 26.75").
This means the 245/35R20 sidewall is 24.50 mm (≈ 0.96") shorter, and the overall diameter is 49.00 mm (≈ 1.93") smaller.
245/45R20 vs 245/35R20 Tire Size Comparison Table
Tire Dimension | 245/45R20 (mm & in) | 245/35R20 (mm & in) | Difference (mm & in) | Percentage Difference |
Section Width | 245 mm (≈ 9.65") | 245 mm (≈ 9.65") | 0 | 0% (vs width) |
Sidewall Height | 110.25 mm (≈ 4.34") | 85.75 mm (≈ 3.38") | 24.50 mm (≈ 0.96") | ≈ 22.22% (vs sidewall) |
Overall Diameter | 728.50 mm (≈ 28.68") | 679.50 mm (≈ 26.75") | 49.00 mm (≈ 1.93") | ≈ 6.73% (vs diameter) |
Circumference | 2288.65 mm (≈ 90.10") | 2134.71 mm (≈ 84.04") | 153.94 mm (≈ 6.06") | ≈ 6.73% (vs diameter) |
Radius | 364.25 mm (≈ 14.34") | 339.75 mm (≈ 13.38") | 24.50 mm (≈ 0.96") | ≈ 6.73% (vs diameter) |
Rim Diameter | 20" | 20" | — | — |
Recommended Rim Width | 7.5–9.0" | 8.0–9.5" | — | — |
Can I use 245/35R20 instead of 245/45R20?
No. Although both tires fit the same 20-inch wheels, the overall diameter reduction of ≈ 6,7% is far beyond acceptable tolerance. This would cause the speedometer to read faster (shown 60 mph would actually mean 55.8 mph), reduce ride height by nearly 1 inch, alter suspension geometry, and noticeably stiffen ride quality. You are losing nearly 1 inch of rubber "cushion." In a 45-series tire, you have a decent air volume; in a 35-series, there is almost no room for the tire to compress over a pothole. This leads to a jarring ride and a high risk of bending your 20-inch wheels. This swap is not suitable for everyday driving.
What Is the Difference Between 245/45R20 vs 235/55R18?
The main differences between 245/45R20 and 235/55R18 are section width, aspect ratio, and rim diameter. The 245/45R20 fits a 20-inch wheel, while the 235/55R18 fits an 18-inch wheel.
The 245/45R20 has an overall diameter of 728.50 mm (≈ 28.68"). The 235/55R18 has a sidewall height of 129.25 mm (≈ 5.09") and an overall diameter of 715.70 mm (≈ 28.18").
This means the 245/45R20 is 10 mm wider, has a 19.00 mm (≈ 0.75") shorter sidewall, and is 12.80 mm (≈ 0.50") larger overall.
245/45R20 vs 235/55R18 Tire Size Comparison Table
Tire Dimension | 245/45R20 (mm & in) | 235/55R18 (mm & in) | Difference (mm & in) | Percentage Difference |
Section Width | 245 mm (≈ 9.65") | 235 mm (≈ 9.25") | 10 mm (≈ 0.39") | ≈ 4.08% (vs width) |
Sidewall Height | 110.25 mm (≈ 4.34") | 129.25 mm (≈ 5.09") | 19.00 mm (≈ 0.75") | ≈ 17.24% (vs sidewall) |
Overall Diameter | 728.50 mm (≈ 28.68") | 715.70 mm (≈ 28.18") | 12.80 mm (≈ 0.50") | ≈ 1.76% (vs diameter) |
Circumference | 2288.65 mm (≈ 90.10") | 2248.44 mm (≈ 88.52") | 40.21 mm (≈ 1.58") | ≈ 1.76% (vs diameter) |
Radius | 364.25 mm (≈ 14.34") | 357.85 mm (≈ 14.09") | 6.40 mm (≈ 0.25") | ≈ 1.76% (vs diameter) |
Rim Diameter | 20" | 18" | — | — |
Recommended Rim Width | 7.5–9.0" | 6.5–8.5" | — | — |
Can I use 235/55R18 instead of 245/45R20?
No. A 235/55R18 tire cannot be mounted on a 20-inch wheel, so it is not interchangeable without changing wheels. If 18-inch wheels are installed, the diameter difference of ≈ 1.7% is within acceptable limits, meaning speedometer accuracy remains close to stock. The taller sidewall generally improves ride comfort, but the wheel change is a required and significant modification. The only major "hidden" hurdle for the swap to 18-inch wheels is brake caliper clearance. Many vehicles that come factory-equipped with 20-inch wheels have large performance brakes. Sometimes, an 18-inch wheel is too small to fit over the metal brake housing (the caliper).
Before buying 18-inch wheels, verify that your specific trim level (e.g., Dodge Charger Scat Pack vs. SXT) allows for 18-inch wheel fitment.
What Is the Difference Between 245/45R20 and 245/45ZR20?
There is no difference in physical dimensions between 245/45R20 and 245/45ZR20. The “Z” designation indicates that the tire is rated for high speeds (historically over 149 mph) and is typically paired with W or Y speed ratings. Fitment, size, and mounting requirements remain the same; only the tire’s speed capability and performance construction differ.
All You Need to Know About 245/45R20 Tires
245/45R20 tires have a section width of 245 millimeters (mm), an aspect ratio of 45%, radial construction, and a 20-inch wheel diameter. This size is common on sporty sedans, performance-oriented crossovers, and luxury vehicles, where drivers want a responsive feel without going extremely low-profile. Before buying 245/45R20 tires, converting measurements into inches, comparing them with similar sizes such as 245/35R20 and 235/55R18, and understanding interchangeability helps avoid clearance issues, wheel-fitment problems, and unintended changes to speedometer accuracy.
What Are the Dimensions of a 245/45R20 Tire in Inches?
A 245/45R20 tire has a section width of 9.65 inches (≈ 9.6") and a sidewall height of 4.34 inches (≈ 4.3"). The overall diameter of a 245/45R20 tire is 28.68 inches (≈ 28.7"), and the circumference is approximately 90.10 inches (≈ 90.1"). The recommended rim width range for the 245/45R20 size is 7.5 to 9.0 inches.
How tall and wide are 245/45R20 tires?
A 245/45R20 tire is approximately 28.68 inches (728.50 mm) tall and 9.65 inches (245 mm) wide.
Recommended 245/45R20 Tires
Well-regarded options in 245/45R20 include:
Comparison of 245/45R20 With Similar Tire Sizes
Comparing 245/45R20 with 245/35R20 and 235/55R18 shows how changes in aspect ratio and wheel diameter affect overall diameter, ride comfort, handling response, and whether a swap is physically possible without changing wheels.
What Is the Difference Between 245/45R20 vs 245/35R20?
The main difference between 245/45R20 and 245/35R20 is the aspect ratio. Both tires fit 20-inch wheels, but the lower-profile 245/35R20 has a much shorter sidewall and a significantly smaller overall diameter.
The 245/45R20 has a sidewall height of 110.25 mm (≈ 4.34") and an overall diameter of 728.50 mm (≈ 28.68"). The 245/35R20 has a sidewall height of 85.75 mm (≈ 3.38") and an overall diameter of 679.50 mm (≈ 26.75").
This means the 245/35R20 sidewall is 24.50 mm (≈ 0.96") shorter, and the overall diameter is 49.00 mm (≈ 1.93") smaller.
245/45R20 vs 245/35R20 Tire Size Comparison Table
Tire Dimension | 245/45R20 (mm & in) | 245/35R20 (mm & in) | Difference (mm & in) | Percentage Difference |
Section Width | 245 mm (≈ 9.65") | 245 mm (≈ 9.65") | 0 | 0% (vs width) |
Sidewall Height | 110.25 mm (≈ 4.34") | 85.75 mm (≈ 3.38") | 24.50 mm (≈ 0.96") | ≈ 22.22% (vs sidewall) |
Overall Diameter | 728.50 mm (≈ 28.68") | 679.50 mm (≈ 26.75") | 49.00 mm (≈ 1.93") | ≈ 6.73% (vs diameter) |
Circumference | 2288.65 mm (≈ 90.10") | 2134.71 mm (≈ 84.04") | 153.94 mm (≈ 6.06") | ≈ 6.73% (vs diameter) |
Radius | 364.25 mm (≈ 14.34") | 339.75 mm (≈ 13.38") | 24.50 mm (≈ 0.96") | ≈ 6.73% (vs diameter) |
Rim Diameter | 20" | 20" | — | — |
Recommended Rim Width | 7.5–9.0" | 8.0–9.5" | — | — |
Can I use 245/35R20 instead of 245/45R20?
No. Although both tires fit the same 20-inch wheels, the overall diameter reduction of ≈ 6,7% is far beyond acceptable tolerance. This would cause the speedometer to read faster (shown 60 mph would actually mean 55.8 mph), reduce ride height by nearly 1 inch, alter suspension geometry, and noticeably stiffen ride quality. You are losing nearly 1 inch of rubber "cushion." In a 45-series tire, you have a decent air volume; in a 35-series, there is almost no room for the tire to compress over a pothole. This leads to a jarring ride and a high risk of bending your 20-inch wheels. This swap is not suitable for everyday driving.
What Is the Difference Between 245/45R20 vs 235/55R18?
The main differences between 245/45R20 and 235/55R18 are section width, aspect ratio, and rim diameter. The 245/45R20 fits a 20-inch wheel, while the 235/55R18 fits an 18-inch wheel.
The 245/45R20 has an overall diameter of 728.50 mm (≈ 28.68"). The 235/55R18 has a sidewall height of 129.25 mm (≈ 5.09") and an overall diameter of 715.70 mm (≈ 28.18").
This means the 245/45R20 is 10 mm wider, has a 19.00 mm (≈ 0.75") shorter sidewall, and is 12.80 mm (≈ 0.50") larger overall.
245/45R20 vs 235/55R18 Tire Size Comparison Table
Tire Dimension | 245/45R20 (mm & in) | 235/55R18 (mm & in) | Difference (mm & in) | Percentage Difference |
Section Width | 245 mm (≈ 9.65") | 235 mm (≈ 9.25") | 10 mm (≈ 0.39") | ≈ 4.08% (vs width) |
Sidewall Height | 110.25 mm (≈ 4.34") | 129.25 mm (≈ 5.09") | 19.00 mm (≈ 0.75") | ≈ 17.24% (vs sidewall) |
Overall Diameter | 728.50 mm (≈ 28.68") | 715.70 mm (≈ 28.18") | 12.80 mm (≈ 0.50") | ≈ 1.76% (vs diameter) |
Circumference | 2288.65 mm (≈ 90.10") | 2248.44 mm (≈ 88.52") | 40.21 mm (≈ 1.58") | ≈ 1.76% (vs diameter) |
Radius | 364.25 mm (≈ 14.34") | 357.85 mm (≈ 14.09") | 6.40 mm (≈ 0.25") | ≈ 1.76% (vs diameter) |
Rim Diameter | 20" | 18" | — | — |
Recommended Rim Width | 7.5–9.0" | 6.5–8.5" | — | — |
Can I use 235/55R18 instead of 245/45R20?
No. A 235/55R18 tire cannot be mounted on a 20-inch wheel, so it is not interchangeable without changing wheels. If 18-inch wheels are installed, the diameter difference of ≈ 1.7% is within acceptable limits, meaning speedometer accuracy remains close to stock. The taller sidewall generally improves ride comfort, but the wheel change is a required and significant modification. The only major "hidden" hurdle for the swap to 18-inch wheels is brake caliper clearance. Many vehicles that come factory-equipped with 20-inch wheels have large performance brakes. Sometimes, an 18-inch wheel is too small to fit over the metal brake housing (the caliper).
Before buying 18-inch wheels, verify that your specific trim level (e.g., Dodge Charger Scat Pack vs. SXT) allows for 18-inch wheel fitment.
What Is the Difference Between 245/45R20 and 245/45ZR20?
There is no difference in physical dimensions between 245/45R20 and 245/45ZR20. The “Z” designation indicates that the tire is rated for high speeds (historically over 149 mph) and is typically paired with W or Y speed ratings. Fitment, size, and mounting requirements remain the same; only the tire’s speed capability and performance construction differ.
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