305/60R18
Overall diameter
32.41″
823 mm
Sidewall height
7.20″
183.0 mm
Tread width
305 mm
12.0″
Circumference
101.82″
8.5 ft
Revs per mile
622
387 per km
Wheel diameter
18″
aspect ratio 60%
Cross-section
- Overall diameter
- 32.41″
- Sidewall (each side)
- 7.20″
- Wheel
- 18″
305/60R18 compared with other sizes
All 32 practical swaps involving 305/60R18 — diameter change, speedometer impact and a fit verdict for each.
305/60R18 → 285/75R16
285/75R16
Diameter −1.3% · Good fit
305/60R18 → 275/70R17
275/70R17
Diameter +0.8% · Good fit
305/60R18 → 285/70R17
285/70R17
Diameter −0.9% · Good fit
305/60R18 → 305/65R17
305/65R17
Diameter −0.6% · Good fit
305/60R18 → 305/70R17
305/70R17
Diameter −4.1% · Marginal fit — proceed with care
305/60R18 → 265/65R18
265/65R18
Diameter +2.7% · Good fit
305/60R18 → 265/70R18
265/70R18
Diameter −0.6% · Good fit
305/60R18 → 275/60R18
275/60R18
Diameter +4.6% · Marginal fit — proceed with care
305/60R18 → 275/65R18
275/65R18
Diameter +1.0% · Good fit
305/60R18 → 275/70R18
275/70R18
Diameter −2.3% · Good fit
305/60R18 → 285/60R18
285/60R18
Diameter +3.0% · Marginal fit — proceed with care
305/60R18 → 285/65R18
285/65R18
Diameter −0.5% · Good fit
305/60R18 → 285/70R18
285/70R18
Diameter −3.9% · Marginal fit — proceed with care
305/60R18 → 295/70R18
295/70R18
Diameter −5.4% · Not recommended
285/65R18 → 305/60R18
285/65R18
Diameter +0.5% · Good fit
265/70R18 → 305/60R18
265/70R18
Diameter +0.6% · Good fit
275/65R18 → 305/60R18
275/65R18
Diameter −1.0% · Good fit
275/70R18 → 305/60R18
275/70R18
Diameter +2.3% · Good fit
265/65R18 → 305/60R18
265/65R18
Diameter −2.6% · Good fit
285/60R18 → 305/60R18
285/60R18
Diameter −2.9% · Good fit
285/70R18 → 305/60R18
285/70R18
Diameter +4.0% · Marginal fit — proceed with care
305/65R17 → 305/60R18
305/65R17
Diameter +0.6% · Good fit
275/60R18 → 305/60R18
275/60R18
Diameter −4.4% · Marginal fit — proceed with care
305/50R20 → 305/60R18
305/50R20
Diameter −1.2% · Good fit
285/55R20 → 305/60R18
285/55R20
Diameter −0.2% · Good fit
265/60R20 → 305/60R18
265/60R20
Diameter +0.3% · Good fit
275/70R17 → 305/60R18
275/70R17
Diameter −0.8% · Good fit
285/70R17 → 305/60R18
285/70R17
Diameter +0.9% · Good fit
305/60R18 → 265/60R20
265/60R20
Diameter −0.3% · Good fit
305/60R18 → 285/55R20
285/55R20
Diameter +0.2% · Good fit
305/60R18 → 305/50R20
305/50R20
Diameter +1.3% · Good fit
305/60R18 → 235/45R18
235/45R18
Diameter +23.1% · Not recommended
Common questions
- What is the overall diameter of a 305/60R18 tire?
- A 305/60R18 tire is about 32.41″ (823 mm) in overall diameter, with a sidewall height of 183.0 mm and a circumference of 101.82″.
- How many revolutions per mile does a 305/60R18 tire turn?
- A 305/60R18 turns roughly 622 revolutions per mile (387 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
- What do the numbers in 305/60R18 mean?
- 305 is the tread width in millimetres, 60 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 305 × 60% = 183.0 mm tall.