225/45R18 tire size
A 225/45R18 tire is 225 mm wide with a 101.3 mm sidewall, 45% of the width, on a 18-inch rim, which puts the whole tire at 659.7 mm, or about 26.0 inches, tall. No model in our data leaves the factory on it, but it can replace the original size on 18 models within 3% of the height.
Overall height
659.7 mm
26.0 in
Sidewall
101.3 mm
45%
Circumference
2,073 mm
Revs per km
483
Actual dimensions of 225/45R18
| Section width | 225 mm (8.9 in) |
| Sidewall height | 101.3 mm (3.99 in) |
| Rim diameter | 18 in (457.2 mm) |
| Overall diameter | 659.7 mm (26.0 in) |
| Circumference | 2,073 mm |
| Revolutions per km | 483 |
| Inch notation (height x width) | 26.0x8.9R18 |
Worked out: sidewall 225 x 0.45 = 101.25 mm, rim 18 x 25.4 = 457.2 mm, overall 457.2 + (101.25 x 2) = 659.7 mm, circumference 3.1416 x 659.7 = 2,073 mm. One turn of the tire moves the car about 2.07 m, which is 483 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 225/45R18 from the factory
No model sold in Thailand in our data leaves the factory on 225/45R18.
Cars that can switch to 225/45R18
These cars leave the factory on another size within 3% of the height of 225/45R18. Whether it fits still depends on rim width and wheel-well clearance.
| Model | Factory size | Height difference | Wheel |
|---|---|---|---|
| Toyota Camry HEV2024–present | 235/45R18 | −1.35% | Same wheel |
| Honda Accord e:HEV2024–present | 235/45R18 | −1.35% | Same wheel |
| MG4 Electric2022–present | 235/45R18 | −1.35% | Same wheel |
| Tesla Model 32024–present | 235/45R18 | −1.35% | Same wheel |
| Mazda32019–present | 215/45R18 | +1.38% | Same wheel |
| Mazda CX-32015–present | 215/50R18 | −1.86% | Same wheel |
| ORA Good Cat2021–present | 215/50R18 | −1.86% | Same wheel |
| Honda Civic (FE)2021–present | 235/40R18 | +2.25% | Same wheel |
| Mitsubishi Xpander Cross HEV2024–present | 205/55R17 | +0.37% | Needs 18-inch wheels |
| Nissan Kicks e-POWERCurrent model | 205/55R17 | +0.37% | Needs 18-inch wheels |
| Honda BR-V2022–present | 215/60R16 | −0.71% | Needs 18-inch wheels |
| Honda WR-V2023–present | 215/60R16 | −0.71% | Needs 18-inch wheels |
Showing the 12 closest of 18 models.
Sizes that can replace 225/45R18
Sizes within ±3% of the overall height of 225/45R18. “At 100 km/h” is the real speed when the speedometer reads 100.
| Size | Height | Difference | At 100 km/h | Sidewall | Match | Compare |
|---|---|---|---|---|---|---|
| 255/35R19 | 661.1 mm | +1.4 mm (+0.21%) | 100.2 km/h | 89.3 mm | Very close | Compare |
| 205/55R17 | 657.3 mm | −2.4 mm (−0.36%) | 99.6 km/h | 112.8 mm | Very close | Compare |
| 225/40R19 | 662.6 mm | +2.9 mm (+0.44%) | 100.4 km/h | 90.0 mm | Very close | Compare |
| 225/50R17 | 656.8 mm | −2.9 mm (−0.44%) | 99.6 km/h | 112.5 mm | Very close | Compare |
| 245/35R19 | 654.1 mm | −5.6 mm (−0.85%) | 99.2 km/h | 85.8 mm | Close | Compare |
| 245/40R18 | 653.2 mm | −6.5 mm (−0.99%) | 99.0 km/h | 98.0 mm | Close | Compare |
| 245/45R17 | 652.3 mm | −7.4 mm (−1.12%) | 98.9 km/h | 110.3 mm | Close | Compare |
| 215/55R17 | 668.3 mm | +8.6 mm (+1.30%) | 101.3 km/h | 118.3 mm | Close | Compare |
- Keeping your wheels, the closest is 245/40R18 at 653.2 mm, −6.5 mm (−0.99%) from the original. With the speedometer on 100 km/h, the car would actually be doing about 99.0 km/h. Ground clearance drops by about 3.3 mm.
- Moving up to 19-inch wheels, the closest height match is 255/35R19 (+0.21%), with the sidewall dropping from 101.3 mm to 89.3 mm.
- Going down to 17-inch wheels, 205/55R17 (−0.36%) is the closest match and raises the sidewall to 112.8 mm.
- A larger or wider tire also changes acceleration, fuel use and steering weight, so look beyond the percentage.
Buying 225/45R18 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 225/45R18
The code after the size on the sidewall, as in 225/45R18 91V, is the load index and speed symbol. The common ratings for this size:
| Version | Index | Per tire | Four tires |
|---|---|---|---|
| Standard load (SL) | 91 | 615 kg | 2,460 kg |
| Extra load (XL) | 95 | 690 kg | 2,760 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
225/45R18 questions
How tall is a 225/45R18 tire?
About 26.0 inches, or 659.7 mm, from top to bottom before it carries weight. Each sidewall is 101.3 mm tall and the tire is 225 mm (8.9 in) wide.
Which cars use 225/45R18 tires?
No car in our data is fitted with 225/45R18 from the factory, but its height is close to the original size on Toyota Camry HEV, Honda Accord e:HEV, MG4 Electric, Tesla Model 3 and Mazda3, so it works as a replacement size.
Can I fit 245/40R18 instead of 225/45R18?
Size-wise, yes: the height differs by −0.99% (−6.5 mm), so an indicated 100 km/h is really about 99.0 km/h. The tread is 20 mm wider. Check rim width and load index first.
How much weight can a 225/45R18 tire carry?
Most standard-load versions carry load index 91: 615 kg per tire, 2,460 kg across four. XL versions are rated 95, or 690 kg per tire. Look for the number after the size on the sidewall, as in 225/45R18 91V.
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.