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 4 bolt x 5 bolt x 6 bolt x 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