245/70R16 tyre size
A 245/70R16 tyre is 245 mm (9.6") wide with a sidewall height of 70 % of the width, i.e. 171.5 mm (6.8"), on a 16" (406 mm) rim. Overall diameter is 749.4 mm (29.5"), so the closest inch-style size is 29.5×9.6R16. Static circumference is 2354 mm; the ETRTO rolling circumference is 2286 mm, giving 438 revolutions per km (704 per mile).
Dimensions and rolling diameter
| Section width | 245 mm | 9.65″ |
| Sidewall height | 171.5 mm | 6.75″ |
| Rim diameter | 406.4 mm | 16″ |
| Overall diameter (static, unloaded) | 749.4 mm | 29.50″ |
| Static radius | 374.7 mm | 14.75″ |
| Static circumference (π × D) | 2,354 mm | 92.7″ |
| Rolling circumference (ETRTO 3.05 × D) | 2,286 mm | 90.0″ |
| Effective rolling radius | 363.8 mm | 14.32″ |
| Revs per km (rolling / static) | 438 / 425 | |
| Inch equivalent | 29.5×9.6R16 | |
| Approved rim widths (approx.) | 6.5″–8″ (measuring rim 7″) | |
A 245/70R16 tyre is 245 mm (9.6") wide with a sidewall height of 70 % of the width, i.e. 171.5 mm (6.8"), on a 16" (406 mm) rim. Overall diameter is 749.4 mm (29.5"), so the closest inch-style size is 29.5×9.6R16. Static circumference is 2354 mm; the ETRTO rolling circumference is 2286 mm, giving 438 revolutions per km (704 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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