265/40R21
Overall diameter
29.35″
745 mm
Sidewall height
4.17″
106.0 mm
Tread width
265 mm
10.4″
Circumference
92.19″
7.7 ft
Revs per mile
687
427 per km
Wheel diameter
21″
aspect ratio 40%
Cross-section
- Overall diameter
- 29.35″
- Sidewall (each side)
- 4.17″
- Wheel
- 21″
265/40R21 compared with other sizes
All 24 practical swaps involving 265/40R21 — diameter change, speedometer impact and a fit verdict for each.
265/40R21 → 265/50R19
265/50R19
Diameter −0.3% · Good fit
265/40R21 → 295/35R20
295/35R20
Diameter +4.3% · Marginal fit — proceed with care
265/40R21 → 235/55R19
235/55R19
Diameter +0.6% · Good fit
265/40R21 → 245/55R19
245/55R19
Diameter −0.9% · Good fit
265/40R21 → 255/50R19
255/50R19
Diameter +1.1% · Good fit
265/40R21 → 245/50R20
245/50R20
Diameter −1.0% · Good fit
265/40R21 → 265/45R20
265/45R20
Diameter −0.1% · Good fit
285/40R21 → 265/40R21
285/40R21
Diameter +2.1% · Good fit
265/45R21 → 265/40R21
265/45R21
Diameter +3.6% · Marginal fit — proceed with care
265/45R20 → 265/40R21
265/45R20
Diameter +0.1% · Good fit
265/50R19 → 265/40R21
265/50R19
Diameter +0.3% · Good fit
275/45R21 → 265/40R21
275/45R21
Diameter +4.8% · Marginal fit — proceed with care
235/55R19 → 265/40R21
235/55R19
Diameter −0.6% · Good fit
245/55R19 → 265/40R21
245/55R19
Diameter +0.9% · Good fit
245/50R20 → 265/40R21
245/50R20
Diameter +1.0% · Good fit
255/50R19 → 265/40R21
255/50R19
Diameter −1.0% · Good fit
255/45R20 → 265/40R21
255/45R20
Diameter −1.1% · Good fit
275/45R20 → 265/40R21
275/45R20
Diameter +1.4% · Good fit
245/45R20 → 265/40R21
245/45R20
Diameter −2.3% · Good fit
275/40R20 → 265/40R21
275/40R20
Diameter −2.3% · Good fit
255/50R20 → 265/40R21
255/50R20
Diameter +2.4% · Good fit
265/40R21 → 265/45R21
265/45R21
Diameter −3.4% · Marginal fit — proceed with care
265/40R21 → 275/45R21
275/45R21
Diameter −4.5% · Marginal fit — proceed with care
265/40R21 → 285/40R21
285/40R21
Diameter −2.1% · Good fit
Common questions
- What is the overall diameter of a 265/40R21 tire?
- A 265/40R21 tire is about 29.35″ (745 mm) in overall diameter, with a sidewall height of 106.0 mm and a circumference of 92.19″.
- How many revolutions per mile does a 265/40R21 tire turn?
- A 265/40R21 turns roughly 687 revolutions per mile (427 per kilometre). This is the number that determines speedometer and odometer accuracy when you change tire size.
- What do the numbers in 265/40R21 mean?
- 265 is the tread width in millimetres, 40 is the aspect ratio — the sidewall height as a percentage of the tread width — and 21 is the wheel diameter in inches. So the sidewall is 265 × 40% = 106.0 mm tall.