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Zeus BCD

Measuring the bolt circle diameter of a Zeus chainring. The trig constant to convert from distance between adjacent bolts to bolt circle diameter for a 5 arm crank is 1/sin(36º) = 1.7013. This measurement verifies that the BCD is 119mm, not 120mm or 118mm.

 

You can google and find these described as anything from 116mm to 122mm.

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Uploaded on October 11, 2011
Taken on October 11, 2011