285/35R22 tyre size
A 285/35R22 tyre is 285 mm (11.2") wide with a sidewall height of 35 % of the width, i.e. 99.8 mm (3.9"), on a 22" (559 mm) rim. Overall diameter is 758.3 mm (29.9"), so the closest inch-style size is 29.9×11.2R22. Static circumference is 2382 mm; the ETRTO rolling circumference is 2313 mm, giving 432 revolutions per km (696 per mile).
Dimensions and rolling diameter
| Section width | 285 mm | 11.22″ |
| Sidewall height | 99.8 mm | 3.93″ |
| Rim diameter | 558.8 mm | 22″ |
| Overall diameter (static, unloaded) | 758.3 mm | 29.85″ |
| Static radius | 379.2 mm | 14.93″ |
| Static circumference (π × D) | 2,382 mm | 93.8″ |
| Rolling circumference (ETRTO 3.05 × D) | 2,313 mm | 91.1″ |
| Effective rolling radius | 368.1 mm | 14.49″ |
| Revs per km (rolling / static) | 432 / 420 | |
| Inch equivalent | 29.9×11.2R22 | |
| Approved rim widths (approx.) | 9.5″–11″ (measuring rim 10″) | |
A 285/35R22 tyre is 285 mm (11.2") wide with a sidewall height of 35 % of the width, i.e. 99.8 mm (3.9"), on a 22" (559 mm) rim. Overall diameter is 758.3 mm (29.9"), so the closest inch-style size is 29.9×11.2R22. Static circumference is 2382 mm; the ETRTO rolling circumference is 2313 mm, giving 432 revolutions per km (696 per mile).
Why two circumferences? The static figure is simple geometry (π × diameter). Under load a radial tyre flattens and rolls about 3 % less per revolution; ETRTO defines the rolling circumference as 3.05 × the nominal diameter, which is what manufacturers quote and what speedo and gearing calculations should use.
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