How To Measure Crank, Chainrings Size BCD

I show how to measure a chainring or crank to be able to replace a chain ring. The main things you need to know are the number of teeth and the BCD (Bolt Center Diameter). Well, and the number of holes. I show what to measure and how to calculate or look up the BCD. As referenced in the video, this is Sheldon Brown s BCD crib sheet: The multipliers I used to calculate BCD by measuring the distance between adjacent bolt holes are: 3 bolt x 1. 155 4 bolt x 1. 414 5 bolt x 1. 699 6 bolt x 2. 000 Some of the most common BCDs: 4 hole: 64mm, 80mm, 104mm, 120mm 5 hole: 74mm, 110mm, 130mm, 135mm SUBSCRIBE HIT THE And please give my video a thumbs up TOOLS SHIRTS WEBPAGE