255/55R20
Overall diameter
31.04″
789 mm
Sidewall height
5.52″
140.3 mm
Tread width
255 mm
10.0″
Circumference
97.53″
8.1 ft
Revs per mile
650
404 per km
Wheel diameter
20″
aspect ratio 55%
Cross-section
- Overall diameter
- 31.04″
- Sidewall (each side)
- 5.52″
- Wheel
- 20″
255/55R20 compared with other sizes
All 30 practical swaps involving 255/55R20 — diameter change, speedometer impact and a fit verdict for each.
255/55R20 → 275/45R20
275/45R20
Diameter +4.4% · Marginal fit — proceed with care
255/55R20 → 275/55R20
275/55R20
Diameter −2.7% · Good fit
255/55R20 → 255/65R18
255/65R18
Diameter −0.0% · Good fit
255/55R20 → 255/60R19
255/60R19
Diameter −0.0% · Good fit
255/55R20 → 275/55R19
275/55R19
Diameter +0.4% · Good fit
255/55R20 → 245/50R20
245/50R20
Diameter +4.7% · Marginal fit — proceed with care
255/55R20 → 255/50R20
255/50R20
Diameter +3.3% · Marginal fit — proceed with care
285/50R20 → 255/55R20
285/50R20
Diameter +0.6% · Good fit
265/55R20 → 255/55R20
265/55R20
Diameter +1.4% · Good fit
265/50R20 → 255/55R20
265/50R20
Diameter −2.0% · Good fit
255/50R20 → 255/55R20
255/50R20
Diameter −3.2% · Marginal fit — proceed with care
275/55R20 → 255/55R20
275/55R20
Diameter +2.8% · Good fit
255/60R19 → 255/55R20
255/60R19
Diameter +0.0% · Good fit
255/65R18 → 255/55R20
255/65R18
Diameter +0.0% · Good fit
275/45R20 → 255/55R20
275/45R20
Diameter −4.2% · Marginal fit — proceed with care
285/55R20 → 255/55R20
285/55R20
Diameter +4.2% · Marginal fit — proceed with care
245/50R20 → 255/55R20
245/50R20
Diameter −4.5% · Marginal fit — proceed with care
265/60R20 → 255/55R20
265/60R20
Diameter +4.8% · Marginal fit — proceed with care
275/60R18 → 255/55R20
275/60R18
Diameter −0.2% · Good fit
285/45R21 → 255/55R20
285/45R21
Diameter +0.2% · Good fit
285/40R22 → 255/55R20
285/40R22
Diameter −0.2% · Good fit
255/55R20 → 265/50R20
265/50R20
Diameter +2.0% · Good fit
255/55R20 → 265/55R20
265/55R20
Diameter −1.4% · Good fit
255/55R20 → 265/60R20
265/60R20
Diameter −4.5% · Marginal fit — proceed with care
255/55R20 → 285/50R20
285/50R20
Diameter −0.6% · Good fit
255/55R20 → 285/55R20
285/55R20
Diameter −4.0% · Marginal fit — proceed with care
255/55R20 → 275/45R21
275/45R21
Diameter +1.0% · Good fit
255/55R20 → 285/45R21
285/45R21
Diameter −0.2% · Good fit
255/55R20 → 275/40R22
275/40R22
Diameter +1.2% · Good fit
255/55R20 → 285/40R22
285/40R22
Diameter +0.2% · Good fit
Common questions
- What is the overall diameter of a 255/55R20 tire?
- A 255/55R20 tire is about 31.04″ (789 mm) in overall diameter, with a sidewall height of 140.3 mm and a circumference of 97.53″.
- How many revolutions per mile does a 255/55R20 tire turn?
- A 255/55R20 turns roughly 650 revolutions per mile (404 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
- What do the numbers in 255/55R20 mean?
- 255 is the tread width in millimetres, 55 is the aspect ratio — the sidewall height as a percentage of the tread width — and 20 is the wheel diameter in inches. So the sidewall is 255 × 55% = 140.3 mm tall.