All-City 130 Bicycle Chainrings
About All-City - "All-City's goal is to make a significant contribution to the equipment and culture of urban cycling. This is not a cash in, this is not a fad, this is our life, our love, our community and our dream. We are a company of riders making products for other riders."
Bolt Circle Diameter (BCD) is the diameter of an imaginary circle running through the center of the chainring mounting holes. It is always defined in millimeters.