245/35R19 tyre size
A 245/35R19 tyre is 245 mm (9.6") wide with a sidewall height of 35 % of the width, i.e. 85.8 mm (3.4"), on a 19" (483 mm) rim. Overall diameter is 654.1 mm (25.8"), so the closest inch-style size is 25.8×9.6R19. Static circumference is 2055 mm; the ETRTO rolling circumference is 1995 mm, giving 501 revolutions per km (807 per mile).
Dimensions and rolling diameter
| Section width | 245 mm | 9.65″ |
| Sidewall height | 85.8 mm | 3.38″ |
| Rim diameter | 482.6 mm | 19″ |
| Overall diameter (static, unloaded) | 654.1 mm | 25.75″ |
| Static radius | 327.0 mm | 12.88″ |
| Static circumference (π × D) | 2,055 mm | 80.9″ |
| Rolling circumference (ETRTO 3.05 × D) | 1,995 mm | 78.5″ |
| Effective rolling radius | 317.5 mm | 12.50″ |
| Revs per km (rolling / static) | 501 / 487 | |
| Inch equivalent | 25.8×9.6R19 | |
| Approved rim widths (approx.) | 8″–9.5″ (measuring rim 8.5″) | |
A 245/35R19 tyre is 245 mm (9.6") wide with a sidewall height of 35 % of the width, i.e. 85.8 mm (3.4"), on a 19" (483 mm) rim. Overall diameter is 654.1 mm (25.8"), so the closest inch-style size is 25.8×9.6R19. Static circumference is 2055 mm; the ETRTO rolling circumference is 1995 mm, giving 501 revolutions per km (807 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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