Originally Posted by
HillRider
I don't understand that. I have a Chorus 10-speed crank that also has the 5th bolt attached to the back of the crank arm. There is a female threaded boss cast into the crankarm with it's outer face in the same plane as the outer faces of the remaining four spider arms and the big chainring sits against it. Then there is a spacer the thickness of the other spider arms that fills in the gap between the big and small chainring. If you filed the odd bolt hole to match the offset bolt, wouldn't standard 110 chainrings fit the same way?
It could be made to work, but requires more than a file. I believe there's a countebore for the bolt head, that would need to be altered, also. It's easy if you have a small milling machine handy.