285/70R18
A 285/70R18 tire is 33.71 inches tall and 11.2 inches wide, with a 7.85-inch sidewall, mounted on a 18-inch wheel.
Overall diameter
33.71″
856 mm
Sidewall height
7.85″
199.5 mm
Tread width
285 mm
11.2″
Circumference
105.90″
8.8 ft
Revs per mile
598
372 per km
Wheel diameter
18″
aspect ratio 70%
Cross-section
- Overall diameter
- 33.71″
- Sidewall (each side)
- 7.85″
- Wheel
- 18″
285/70R18 in inches and millimeters
Every dimension of a 285/70R18, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 33.71″ | 856 mm |
| Tread width | 11.2″ | 285 mm |
| Sidewall height | 7.85″ | 199.5 mm |
| Wheel diameter | 18″ | 457 mm |
| Circumference | 105.90″ | 2690 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.
285/70R18 compared with other sizes
All 29 practical swaps involving 285/70R18 — diameter change, speedometer impact and a fit verdict for each.
285/70R18 → 285/75R16
285/75R16
Diameter +2.7% · This fits
285/70R18 → 305/70R17
305/70R17
Diameter −0.3% · This fits
285/70R18 → 315/70R17
315/70R17
Diameter −1.9% · This fits
285/70R18 → 255/70R18
255/70R18
Diameter +5.2% · Too big a jump
285/70R18 → 265/70R18
265/70R18
Diameter +3.4% · Borderline. Check clearance first
285/70R18 → 275/70R18
275/70R18
Diameter +1.7% · This fits
285/70R18 → 285/65R18
285/65R18
Diameter +3.4% · Borderline. Check clearance first
295/70R18 → 285/70R18
295/70R18
Diameter +1.6% · This fits
275/70R18 → 285/70R18
275/70R18
Diameter −1.6% · This fits
285/65R18 → 285/70R18
285/65R18
Diameter −3.3% · Borderline. Check clearance first
265/70R18 → 285/70R18
265/70R18
Diameter −3.3% · Borderline. Check clearance first
305/60R18 → 285/70R18
305/60R18
Diameter −3.9% · Borderline. Check clearance first
285/60R20 → 285/70R18
285/60R20
Diameter −0.7% · This fits
275/65R18 → 285/70R18
275/65R18
Diameter −4.8% · Borderline. Check clearance first
255/70R18 → 285/70R18
255/70R18
Diameter −4.9% · Borderline. Check clearance first
305/70R17 → 285/70R18
305/70R17
Diameter +0.3% · This fits
295/60R20 → 285/70R18
295/60R20
Diameter +0.7% · This fits
275/65R20 → 285/70R18
275/65R20
Diameter +1.1% · This fits
285/65R20 → 285/70R18
285/65R20
Diameter +2.6% · This fits
285/75R16 → 285/70R18
285/75R16
Diameter −2.6% · This fits
305/55R20 → 285/70R18
305/55R20
Diameter −1.5% · This fits
285/70R18 → 295/70R18
295/70R18
Diameter −1.6% · This fits
285/70R18 → 305/60R18
305/60R18
Diameter +4.0% · Borderline. Check clearance first
285/70R18 → 275/65R20
275/65R20
Diameter −1.1% · This fits
285/70R18 → 285/60R20
285/60R20
Diameter +0.7% · This fits
285/70R18 → 285/65R20
285/65R20
Diameter −2.5% · This fits
285/70R18 → 295/60R20
295/60R20
Diameter −0.7% · This fits
285/70R18 → 295/65R20
295/65R20
Diameter −4.0% · Borderline. Check clearance first
285/70R18 → 235/45R18
235/45R18
Diameter +28.0% · Too big a jump
Common questions
- What is 285/70R18 in inches?
- A 285/70R18 tire is 33.71 inches tall and 11.2 inches wide, with a 7.85-inch sidewall, mounted on a 18-inch wheel. In metric that is 856 mm tall and 285 mm wide. The circumference is 105.90 inches.
- How tall is a 285/70R18 tire?
- 33.71 inches, or 856 mm. That is the overall diameter, wheel included. It turns about 598 times per mile, which is what your speedometer counts.
- What do the numbers in 285/70R18 mean?
- 285 is the tread width in millimeters, 70 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 285 × 70% = 199.5 mm tall.