285/70R18
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 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% · Good fit
285/70R18 → 305/70R17
305/70R17
Diameter −0.3% · Good fit
285/70R18 → 315/70R17
315/70R17
Diameter −1.9% · Good fit
285/70R18 → 255/70R18
255/70R18
Diameter +5.2% · Not recommended
285/70R18 → 265/70R18
265/70R18
Diameter +3.4% · Marginal fit — proceed with care
285/70R18 → 275/70R18
275/70R18
Diameter +1.7% · Good fit
285/70R18 → 285/65R18
285/65R18
Diameter +3.4% · Marginal fit — proceed with care
295/70R18 → 285/70R18
295/70R18
Diameter +1.6% · Good fit
275/70R18 → 285/70R18
275/70R18
Diameter −1.6% · Good fit
285/65R18 → 285/70R18
285/65R18
Diameter −3.3% · Marginal fit — proceed with care
265/70R18 → 285/70R18
265/70R18
Diameter −3.3% · Marginal fit — proceed with care
305/60R18 → 285/70R18
305/60R18
Diameter −3.9% · Marginal fit — proceed with care
285/60R20 → 285/70R18
285/60R20
Diameter −0.7% · Good fit
275/65R18 → 285/70R18
275/65R18
Diameter −4.8% · Marginal fit — proceed with care
255/70R18 → 285/70R18
255/70R18
Diameter −4.9% · Marginal fit — proceed with care
305/70R17 → 285/70R18
305/70R17
Diameter +0.3% · Good fit
295/60R20 → 285/70R18
295/60R20
Diameter +0.7% · Good fit
275/65R20 → 285/70R18
275/65R20
Diameter +1.1% · Good fit
285/65R20 → 285/70R18
285/65R20
Diameter +2.6% · Good fit
285/75R16 → 285/70R18
285/75R16
Diameter −2.6% · Good fit
305/55R20 → 285/70R18
305/55R20
Diameter −1.5% · Good fit
285/70R18 → 295/70R18
295/70R18
Diameter −1.6% · Good fit
285/70R18 → 305/60R18
305/60R18
Diameter +4.0% · Marginal fit — proceed with care
285/70R18 → 275/65R20
275/65R20
Diameter −1.1% · Good fit
285/70R18 → 285/60R20
285/60R20
Diameter +0.7% · Good fit
285/70R18 → 285/65R20
285/65R20
Diameter −2.5% · Good fit
285/70R18 → 295/60R20
295/60R20
Diameter −0.7% · Good fit
285/70R18 → 295/65R20
295/65R20
Diameter −4.0% · Marginal fit — proceed with care
285/70R18 → 235/45R18
235/45R18
Diameter +28.0% · Not recommended
Common questions
- What is the overall diameter of a 285/70R18 tire?
- A 285/70R18 tire is about 33.71″ (856 mm) in overall diameter, with a sidewall height of 199.5 mm and a circumference of 105.90″.
- How many revolutions per mile does a 285/70R18 tire turn?
- A 285/70R18 turns roughly 598 revolutions per mile (372 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
- What do the numbers in 285/70R18 mean?
- 285 is the tread width in millimetres, 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.