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Save 20% Off In-Stock Regular Priced Helmets through June 30th with the code HELMET20 at checkout.
Save 20% Off In-Stock Regular Priced Helmets through June 30th with the code HELMET20 at checkout.

Chainring Bolt Circle Diameter Measurement

It's important to have the correct bolt circle diameter (BCD) when ordering replacement chainrings. Use the diagram and chart below to determine your BCD:

Chainring BCD

Measure the distance in millimeters between two adjacent chainring mounting holes (center to center). Use this distance (x) to find your BCD in the chart below:

Bolt Circle Diameter Chart