255/45R18 tire size
A 255/45R18 tire is 255 mm wide with a 114.8 mm sidewall, 45% of the width, on a 18-inch rim, which puts the whole tire at 686.7 mm, or about 27.0 inches, tall. No model in our data leaves the factory on it, but it can replace the original size on 13 models within 3% of the height.
Overall height
686.7 mm
27.0 in
Sidewall
114.8 mm
45%
Circumference
2,157 mm
Revs per km
464
Actual dimensions of 255/45R18
| Section width | 255 mm (10.0 in) |
| Sidewall height | 114.8 mm (4.52 in) |
| Rim diameter | 18 in (457.2 mm) |
| Overall diameter | 686.7 mm (27.0 in) |
| Circumference | 2,157 mm |
| Revolutions per km | 464 |
| Inch notation (height x width) | 27.0x10.0R18 |
Worked out: sidewall 255 x 0.45 = 114.75 mm, rim 18 x 25.4 = 457.2 mm, overall 457.2 + (114.75 x 2) = 686.7 mm, circumference 3.1416 x 686.7 = 2,157 mm. One turn of the tire moves the car about 2.16 m, which is 464 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 255/45R18 from the factory
No model sold in Thailand in our data leaves the factory on 255/45R18.
Cars that can switch to 255/45R18
These cars leave the factory on another size within 3% of the height of 255/45R18. Whether it fits still depends on rim width and wheel-well clearance.
| Model | Factory size | Height difference | Wheel |
|---|---|---|---|
| Toyota C-HR2018–2023 | 225/50R18 | +0.66% | Same wheel |
| Toyota Corolla Cross2020–present | 225/50R18 | +0.66% | Same wheel |
| Toyota Innova Zenix HEV2023–present | 225/50R18 | +0.66% | Same wheel |
| Honda e:N12024–present | 225/50R18 | +0.66% | Same wheel |
| Honda HR-V e:HEV2022–present | 225/50R18 | +0.66% | Same wheel |
| Mitsubishi Xforce HEVCurrent model | 225/50R18 | +0.66% | Same wheel |
| BYD Seal2023–present | 225/50R18 | +0.66% | Same wheel |
| MG HS / HS PHEVCurrent model | 235/50R18 | −0.79% | Same wheel |
| BYD ATTO 32022–present | 235/50R18 | −0.79% | Same wheel |
| Toyota Camry HEV2024–present | 235/45R18 | +2.69% | Same wheel |
| Honda Accord e:HEV2024–present | 235/45R18 | +2.69% | Same wheel |
| MG4 Electric2022–present | 235/45R18 | +2.69% | Same wheel |
Showing the 12 closest of 13 models.
Sizes that can replace 255/45R18
Sizes within ±3% of the overall height of 255/45R18. “At 100 km/h” is the real speed when the speedometer reads 100.
| Size | Height | Difference | At 100 km/h | Sidewall | Match | Compare |
|---|---|---|---|---|---|---|
| 255/40R19 | 686.6 mm | −0.1 mm (−0.01%) | 100.0 km/h | 102.0 mm | Very close | Compare |
| 255/35R20 | 686.5 mm | −0.2 mm (−0.03%) | 100.0 km/h | 89.3 mm | Very close | Compare |
| 225/45R19 | 685.1 mm | −1.6 mm (−0.23%) | 99.8 km/h | 101.3 mm | Very close | Compare |
| 235/55R17 | 690.3 mm | +3.6 mm (+0.52%) | 100.5 km/h | 129.3 mm | Close | Compare |
| 225/50R18 | 682.2 mm | −4.5 mm (−0.66%) | 99.3 km/h | 112.5 mm | Close | Compare |
| 235/50R18 | 692.2 mm | +5.5 mm (+0.80%) | 100.8 km/h | 117.5 mm | Close | Compare |
| 245/35R20 | 679.5 mm | −7.2 mm (−1.05%) | 99.0 km/h | 85.8 mm | Close | Compare |
| 235/45R19 | 694.1 mm | +7.4 mm (+1.08%) | 101.1 km/h | 105.8 mm | Close | Compare |
- Keeping your wheels, the closest is 225/50R18 at 682.2 mm, −4.5 mm (−0.66%) from the original. With the speedometer on 100 km/h, the car would actually be doing about 99.3 km/h. Ground clearance drops by about 2.3 mm.
- Moving up to 19-inch wheels, the closest height match is 255/40R19 (−0.01%), with the sidewall dropping from 114.8 mm to 102.0 mm.
- Going down to 17-inch wheels, 235/55R17 (+0.52%) is the closest match and raises the sidewall to 129.3 mm.
- A larger or wider tire also changes acceleration, fuel use and steering weight, so look beyond the percentage.
Buying 255/45R18 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 255/45R18
The code after the size on the sidewall, as in 255/45R18 99V, is the load index and speed symbol. The common ratings for this size:
| Version | Index | Per tire | Four tires |
|---|---|---|---|
| Standard load (SL) | 99 | 775 kg | 3,100 kg |
| Extra load (XL) | 103 | 875 kg | 3,500 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
255/45R18 questions
How tall is a 255/45R18 tire?
About 27.0 inches, or 686.7 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 255/45R18 tires?
No car in our data is fitted with 255/45R18 from the factory, but its height is close to the original size on Toyota C-HR, Toyota Corolla Cross, Toyota Innova Zenix HEV, Honda e:N1 and Honda HR-V e:HEV, so it works as a replacement size.
Can I fit 225/50R18 instead of 255/45R18?
Size-wise, yes: the height differs by −0.66% (−4.5 mm), so an indicated 100 km/h is really about 99.3 km/h. The tread is 30 mm narrower. Check rim width and load index first.
How much weight can a 255/45R18 tire carry?
Most standard-load versions carry load index 99: 775 kg per tire, 3,100 kg across four. XL versions are rated 103, or 875 kg per tire. Look for the number after the size on the sidewall, as in 255/45R18 99V.
Other 18-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.