245/45R18
A 245/45R18 tire is 26.68 inches tall and 9.6 inches wide, with a 4.34-inch sidewall, mounted on a 18-inch wheel.
Common fitments: Charger, Camaro, ES 350
Overall diameter
26.68″
678 mm
Sidewall height
4.34″
110.3 mm
Tread width
245 mm
9.6″
Circumference
83.82″
7.0 ft
Revs per mile
756
470 per km
Wheel diameter
18″
aspect ratio 45%
Cross-section
- Overall diameter
- 26.68″
- Sidewall (each side)
- 4.34″
- Wheel
- 18″
245/45R18 in inches and millimeters
Every dimension of a 245/45R18, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 26.68″ | 678 mm |
| Tread width | 9.6″ | 245 mm |
| Sidewall height | 4.34″ | 110.3 mm |
| Wheel diameter | 18″ | 457 mm |
| Circumference | 83.82″ | 2129 mm |
Nominal dimensions from the size code. A real tire varies by a few millimeters between manufacturers, and a loaded tire sits slightly shorter than its free diameter.
245/45R18 compared with other sizes
All 31 practical swaps involving 245/45R18 — diameter change, speedometer impact and a fit verdict for each.
245/45R18 → 215/65R16
215/65R16
Diameter −1.2% · Fitment not determined
245/45R18 → 225/60R16
225/60R16
Diameter +0.2% · Fitment not determined
245/45R18 → 235/60R16
235/60R16
Diameter −1.6% · Fitment not determined
245/45R18 → 225/55R17
225/55R17
Diameter −0.2% · Fitment not determined
245/45R18 → 225/45R18
225/45R18
Diameter +2.7% · Fitment not determined
245/45R18 → 235/40R18
235/40R18
Diameter +5.0% · Fitment not determined
245/45R18 → 235/45R18
235/45R18
Diameter +1.3% · Fitment not determined
245/45R18 → 235/50R18
235/50R18
Diameter −2.1% · Fitment not determined
245/45R18 → 245/40R18
245/40R18
Diameter +3.8% · Fitment not determined
255/45R18 → 245/45R18
255/45R18
Diameter +1.3% · Fitment not determined
235/45R18 → 245/45R18
235/45R18
Diameter −1.3% · Fitment not determined
235/50R18 → 245/45R18
235/50R18
Diameter +2.1% · Fitment not determined
245/40R18 → 245/45R18
245/40R18
Diameter −3.6% · Fitment not determined
255/40R18 → 245/45R18
255/40R18
Diameter −2.4% · Fitment not determined
225/45R18 → 245/45R18
225/45R18
Diameter −2.7% · Fitment not determined
245/40R19 → 245/45R18
245/40R19
Diameter +0.1% · Fitment not determined
245/35R20 → 245/45R18
245/35R20
Diameter +0.3% · Fitment not determined
235/40R18 → 245/45R18
235/40R18
Diameter −4.8% · Fitment not determined
225/60R16 → 245/45R18
225/60R16
Diameter −0.2% · Fitment not determined
225/55R17 → 245/45R18
225/55R17
Diameter +0.2% · Fitment not determined
205/65R16 → 245/45R18
205/65R16
Diameter −0.7% · Fitment not determined
235/40R19 → 245/45R18
235/40R19
Diameter −1.0% · Fitment not determined
215/65R16 → 245/45R18
215/65R16
Diameter +1.2% · Fitment not determined
245/45R18 → 235/40R19
235/40R19
Diameter +1.1% · Fitment not determined
245/45R18 → 245/40R19
245/40R19
Diameter −0.1% · Fitment not determined
245/45R18 → 245/35R20
245/35R20
Diameter −0.3% · Fitment not determined
245/45R18 → 255/35R20
255/35R20
Diameter −1.3% · Fitment not determined
245/45R18 → 205/65R16
205/65R16
Diameter +0.7% · Fitment not determined
245/45R18 → 235/55R18
235/55R18
Diameter −5.3% · Fitment not determined
245/45R18 → 255/40R18
255/40R18
Diameter +2.5% · Fitment not determined
245/45R18 → 255/45R18
255/45R18
Diameter −1.3% · Fitment not determined
Common questions
- What is 245/45R18 in inches?
- A 245/45R18 tire is 26.68 inches tall and 9.6 inches wide, with a 4.34-inch sidewall, mounted on a 18-inch wheel. In metric that is 678 mm tall and 245 mm wide. The circumference is 83.82 inches.
- How tall is a 245/45R18 tire?
- 26.68 inches, or 678 mm. That is the overall diameter, wheel included. It turns about 756 times per mile, which is what your speedometer counts.
- What do the numbers in 245/45R18 mean?
- 245 is the tread width in millimeters, 45 is the aspect ratio — the sidewall height as a percentage of the tread width — and 18 is the wheel diameter in inches. So the sidewall is 245 × 45% = 110.3 mm tall.