chainring diameter question

[TK421]

would I be right in thinking that a chainring with a 110mm BCD will have the same overall diameter as a chainring with a 130mm BCD? ie a 53 tooth ring would have the same overall diameter whether 110mm BCD or 130mm BCD. If I need to sit in the corner wearing that lovely conical hat with a "D" on it please let me know.

 

[LittleWheelsandBig]

Yes, unless one of them is a non-round chainring.

 

[CXRAndy]

BCD is the Bolt circle diameter. Nothing to do with external toothed diameter

 

[TK421]

Yes, unless one of them is a non-round chainring.

Of course sir. Of

BCD is the Bolt circle diameter. Nothing to do with external toothed diameter

Exactly what I was thinking. Just wanted to clarify.
Thank you both for the speedy response, and not mentioning that lovely conical hat.

 

[slowmotion]

BCD is the diameterof the circle on which the holes that fix the chainring sits. For a given BCD, you can have a variety of different tooth counts, all with different overall chainring diameters.