How to Measure BCD

[Spiderweb]

I have a 2009 Specialized Epic MTB with a triple chainset. I would like to order some 4 bolt chainrings, would anyone know the Bolt Circle Diameter or if not let me know how to measure.

Thank you

 

[Jody]

I have a 2009 Specialized Epic MTB with a triple chainset. I would like to order some 4 bolt chainrings, would anyone know the Bolt Circle Diameter or if not let me know how to measure.

Thank you

104BCD if a Shimano M660 SLX chainset.

Measure the centre of one bolt to the opposing side for BCD (if symmetric )

 

[Ming the Merciless]

https://www.wolftoothcomponents.com/pages/how-to-measure-bolt-circle-diameter-bcd

 

[Ajax Bay]

https://sheldonbrown.com/cribsheet-bcd.html

 

[Spiderweb]

Thank you for your replies.
I don’t have the bike here to measure right now but looking at the calculators above it seems as though the 2 bigger chainrings are 104 bcd and the 22t granny ring 64 bcd?

 

[T4tomo]

it seems as though the 2 bigger chainrings are 104 bcd and the 22t granny ring 64 bcd?

Yes indeed