The 225/45R18 is a common tire size for midsize sedans such as Toyota Camry, Honda Accord, and Hyundai Sonata.
With a 101.3 mm sidewall (45% aspect ratio), this tire offers a balanced blend of ride comfort and handling precision — versatile for both city driving and spirited cornering.
Compared to the baseline 235/45R18, this tire's overall diameter differs by -1.3% — a speedometer calibrated for 235/45R18 would read 101.4 km/h at an actual 100 km/h.
OE on the BMW 3 Series (F30 M-Sport), BMW 2 Series (G42), Audi A4 (B8/B9 18" packages), Mercedes-Benz C-Class (W204/W205 Sport) and Mercedes A-Class (W177). Load index 91W or 95Y reinforced. Together with 225/40R18, the most-stocked premium-sedan replacement size in the US northeast and Europe.
Mainstream sedan sizes balance compound longevity against light all-season handling. When replacing, match the OE speed rating (H or V on most trims) — installing a lower rating voids many manufacturer load-test certifications and is illegal on autobahn-rated vehicles. Wheel-well clearance is rarely a concern at this rim diameter; speedometer drift across factory alternatives stays well inside the ±3% legal window.
| Tire Code | 225/45R18 |
| Section Width | 225 mm |
| Aspect Ratio | 45% |
| Rim Diameter | 18" |
| Sidewall Height | 101.3 mm |
| Overall Diameter | 659.7 mm / 25.97" |
| Circumference | 2072.5 mm / 81.59" |
| Revolutions per km | 482.5 |
| Revolutions per mile | 776.5 |
| Tire Code | OD (mm) | Δ mm | Δ % | Speedo at 100 km/h |
|---|---|---|---|---|
| 225/45R17 | 634.3 | -25.4 | -3.9% | 104.0 |
| 225/40R18 | 637.2 | -22.5 | -3.4% | 103.5 |
| 215/45R18 | 650.7 | -9.0 | -1.4% | 101.4 |
| 225/45R18 (current) | 659.7 | — | — | 100.0 |
| 235/45R18 | 668.7 | +9.0 | +1.4% | 98.7 |