The base formula for the minimum chain length is given below. This minimum length is increased by 1" for 2x and 3x transmissions; 2" for 1x.

$$\frac{1}{4}\times (F+R)+2\times \sqrt{C^2+(0.0796\times (F-R){)}^2}$$

The minimum value is rounded to the nearest integer for sliding dropouts (e.g. track ends). The value is rounded up for fixed chainstays (e.g. vertical dropouts).

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