255/45R20 tire size
A 255/45R20 tire is 255 mm wide with a 114.8 mm sidewall, 45% of the width, on a 20-inch rim, which puts the whole tire at 737.5 mm, or about 29.0 inches, tall. No model in our data leaves the factory on it, but it can replace the original size on 5 models within 3% of the height.
Overall height
737.5 mm
29.0 in
Sidewall
114.8 mm
45%
Circumference
2,317 mm
Revs per km
432
Actual dimensions of 255/45R20
| Section width | 255 mm (10.0 in) |
| Sidewall height | 114.8 mm (4.52 in) |
| Rim diameter | 20 in (508.0 mm) |
| Overall diameter | 737.5 mm (29.0 in) |
| Circumference | 2,317 mm |
| Revolutions per km | 432 |
| Inch notation (height x width) | 29.0x10.0R20 |
Worked out: sidewall 255 x 0.45 = 114.75 mm, rim 20 x 25.4 = 508 mm, overall 508 + (114.75 x 2) = 737.5 mm, circumference 3.1416 x 737.5 = 2,317 mm. One turn of the tire moves the car about 2.32 m, which is 432 turns per kilometer. New to sidewall codes? See how to read a tire size.
These are nominal figures from the standard formula. Real tires vary slightly by brand and squat a little under the weight of the car.
Cars fitted with 255/45R20 from the factory
No model sold in Thailand in our data leaves the factory on 255/45R20.
Cars that can switch to 255/45R20
These cars leave the factory on another size within 3% of the height of 255/45R20. Whether it fits still depends on rim width and wheel-well clearance.
| Model | Factory size | Height difference | Wheel |
|---|---|---|---|
| BYD Sealion 72025–present | 245/45R20 | +1.24% | Same wheel |
| Honda CR-V2023–present | 235/60R18 | −0.23% | Needs 20-inch wheels |
| Honda CR-V2017–2022 | 235/60R18 | −0.23% | Needs 20-inch wheels |
| Mazda CX-52017–present | 225/55R19 | +1.01% | Needs 20-inch wheels |
| BYD Sealion 6 DM-i2024–present | 235/50R19 | +2.77% | Needs 20-inch wheels |
Sizes that can replace 255/45R20
Sizes within ±3% of the overall height of 255/45R20. “At 100 km/h” is the real speed when the speedometer reads 100.
| Size | Height | Difference | At 100 km/h | Sidewall | Match | Compare |
|---|---|---|---|---|---|---|
| 255/50R19 | 737.6 mm | +0.1 mm (+0.01%) | 100.0 km/h | 127.5 mm | Very close | Compare |
| 235/55R19 | 741.1 mm | +3.6 mm (+0.49%) | 100.5 km/h | 129.3 mm | Very close | Compare |
| 225/55R19 | 730.1 mm | −7.4 mm (−1.00%) | 99.0 km/h | 123.8 mm | Close | Compare |
| 245/45R20 | 728.5 mm | −9.0 mm (−1.22%) | 98.8 km/h | 110.3 mm | Close | Compare |
| 265/45R20 | 746.5 mm | +9.0 mm (+1.22%) | 101.2 km/h | 119.3 mm | Close | Compare |
| 245/55R19 | 752.1 mm | +14.6 mm (+1.98%) | 102.0 km/h | 134.8 mm | Close | Compare |
| 235/50R19 | 717.6 mm | −19.9 mm (−2.70%) | 97.3 km/h | 117.5 mm | Within range | Compare |
- Keeping your wheels, the closest is 245/45R20 at 728.5 mm, −9.0 mm (−1.22%) from the original. With the speedometer on 100 km/h, the car would actually be doing about 98.8 km/h. Ground clearance drops by about 4.5 mm.
- Going down to 19-inch wheels, 255/50R19 (+0.01%) is the closest match and raises the sidewall to 127.5 mm.
Buying 255/45R20 tires
Low-profile sizes are mostly performance tires and price rises with W or Y speed ratings; comfort-focused models exist in the same size if you do not drive hard.
Check the production date in the DOT code before paying.
Check current prices
Search by brand
Links open marketplace search results; prices change constantly and not every brand makes this size.
Load index and speed rating for 255/45R20
The code after the size on the sidewall, as in 255/45R20 101V, is the load index and speed symbol. The common ratings for this size:
| Version | Index | Per tire | Four tires |
|---|---|---|---|
| Standard load (SL) | 101 | 825 kg | 3,300 kg |
| Extra load (XL) | 105 | 925 kg | 3,700 kg |
The new tire's load index and speed symbol must be no lower than the door placard, and it only carries its rated load at the correct pressure.
Common speed symbols in this size
V
240 km/h
W
270 km/h
255/45R20 questions
How tall is a 255/45R20 tire?
About 29.0 inches, or 737.5 mm, from top to bottom before it carries weight. Each sidewall is 114.8 mm tall and the tire is 255 mm (10.0 in) wide.
Which cars use 255/45R20 tires?
No car in our data is fitted with 255/45R20 from the factory, but its height is close to the original size on BYD Sealion 7, Honda CR-V, Mazda CX-5 and BYD Sealion 6 DM-i, so it works as a replacement size.
Can I fit 245/45R20 instead of 255/45R20?
Size-wise, yes: the height differs by −1.22% (−9.0 mm), so an indicated 100 km/h is really about 98.8 km/h. The tread is 10 mm narrower. Check rim width and load index first.
How much weight can a 255/45R20 tire carry?
Most standard-load versions carry load index 101: 825 kg per tire, 3,300 kg across four. XL versions are rated 105, or 925 kg per tire. Look for the number after the size on the sidewall, as in 255/45R20 101V.
Other 20-inch sizes
To compare other sizes yourself, use the tire size calculator; changing rim size, try plus/minus sizing; and see speedometer error by speed.