"bcd" term in chainring
07-18-07 | 06:14 PM
#2
Your mom
Joined: Aug 2006
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Bolt Center Diameter. Literally, if you were to draw a circle through the center of the chainring bolts, the diameter of that circle is the measure referred to. Usually specific to a manufacturer. Easier to research what goes with your crank than to try and measure yourself.
07-18-07 | 06:19 PM
#3
Decrepit Member
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From: Santa Rosa, California
Bikes: Waterford 953 RS-22, several Paramounts
07-18-07 | 06:30 PM
#4
Senior Member
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From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Four 4-bolt chainrings the BCD is easy to measure, just measure the distance across two opposing bolts. For 5-bolt cranks it's not so straight forward so the usual method is to measure the distance between two adjacent bolts and look up a conversion chart such as Sheldon Brown's.
