bolt centre diameter
the distance from the centre of the spindle to where the chainring bolts go
i guess it all relates to the length of the spider arms on the crank
It's bolt circle diameter actually.
And it's not from the centre of the bb spindle to the chainring bolt - that would be the radius, not the diameter.
It's the width of an imaginary circle whose line goes through all the chainring bolts.
It's bolt circle diameter actually.
And it's not from the centre of the bb spindle to the chainring bolt - that would be the radius, not the diameter.
It's the width of an imaginary circle whose line goes through all the chainring bolts.