235/55R18
A 235/55R18 tire is 28.18 inches tall and 9.3 inches wide, with a 5.09-inch sidewall, mounted on a 18-inch wheel.
Overall diameter
28.18″
716 mm
Sidewall height
5.09″
129.3 mm
Tread width
235 mm
9.3″
Circumference
88.52″
7.4 ft
Revs per mile
716
445 per km
Wheel diameter
18″
aspect ratio 55%
Cross-section
- Overall diameter
- 28.18″
- Sidewall (each side)
- 5.09″
- Wheel
- 18″
235/55R18 in inches and millimeters
Every dimension of a 235/55R18, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 28.18″ | 716 mm |
| Tread width | 9.3″ | 235 mm |
| Sidewall height | 5.09″ | 129.3 mm |
| Wheel diameter | 18″ | 457 mm |
| Circumference | 88.52″ | 2248 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.
235/55R18 compared with other sizes
All 30 practical swaps involving 235/55R18 — diameter change, speedometer impact and a fit verdict for each.
235/55R18 → 235/50R18
235/50R18
Diameter +3.4% · Borderline. Check clearance first
235/55R18 → 235/60R18
235/60R18
Diameter −3.2% · Borderline. Check clearance first
235/55R18 → 255/55R18
255/55R18
Diameter −3.0% · This fits
235/55R18 → 215/70R16
215/70R16
Diameter +1.2% · This fits
235/55R18 → 225/70R16
225/70R16
Diameter −0.8% · This fits
235/55R18 → 235/70R16
235/70R16
Diameter −2.7% · This fits
235/55R18 → 215/65R17
215/65R17
Diameter +0.6% · This fits
235/55R18 → 225/65R17
225/65R17
Diameter −1.2% · This fits
235/55R18 → 235/60R17
235/60R17
Diameter +0.3% · This fits
235/55R18 → 225/60R18
225/60R18
Diameter −1.6% · This fits
225/60R18 → 235/55R18
225/60R18
Diameter +1.6% · This fits
235/60R18 → 235/55R18
235/60R18
Diameter +3.3% · Borderline. Check clearance first
235/50R18 → 235/55R18
235/50R18
Diameter −3.3% · Borderline. Check clearance first
255/55R18 → 235/55R18
255/55R18
Diameter +3.1% · Borderline. Check clearance first
235/50R19 → 235/55R18
235/50R19
Diameter +0.3% · This fits
235/60R17 → 235/55R18
235/60R17
Diameter −0.3% · This fits
255/45R18 → 235/55R18
255/45R18
Diameter −4.1% · Borderline. Check clearance first
245/60R18 → 235/55R18
245/60R18
Diameter +5.0% · Borderline. Check clearance first
245/45R18 → 235/55R18
245/45R18
Diameter −5.3% · Too big a jump
255/45R19 → 235/55R18
255/45R19
Diameter −0.5% · This fits
215/65R17 → 235/55R18
215/65R17
Diameter −0.6% · This fits
225/70R16 → 235/55R18
225/70R16
Diameter +0.8% · This fits
215/70R16 → 235/55R18
215/70R16
Diameter −1.2% · This fits
225/65R17 → 235/55R18
225/65R17
Diameter +1.2% · This fits
235/55R18 → 245/60R18
245/60R18
Diameter −4.7% · Borderline. Check clearance first
235/55R18 → 255/45R18
255/45R18
Diameter +4.2% · Borderline. Check clearance first
235/55R18 → 235/50R19
235/50R19
Diameter −0.3% · This fits
235/55R18 → 255/45R19
255/45R19
Diameter +0.5% · This fits
235/55R18 → 245/40R20
245/40R20
Diameter +1.7% · This fits
235/55R18 → 235/45R18
235/45R18
Diameter +7.0% · Too big a jump
Common questions
- What is 235/55R18 in inches?
- A 235/55R18 tire is 28.18 inches tall and 9.3 inches wide, with a 5.09-inch sidewall, mounted on a 18-inch wheel. In metric that is 716 mm tall and 235 mm wide. The circumference is 88.52 inches.
- How tall is a 235/55R18 tire?
- 28.18 inches, or 716 mm. That is the overall diameter, wheel included. It turns about 716 times per mile, which is what your speedometer counts.
- What do the numbers in 235/55R18 mean?
- 235 is the tread width in millimeters, 55 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 235 × 55% = 129.3 mm tall.