Originally Posted by
seypat
The Takagi triple I have uses the smaller bolts also. I have a Sakae CR crank as well. The smaller bolts are out there. The spacers are common as well. Measure the thickness of the middle chainring where it attaches to the crank. That is the thickness of the spacer you need.
I'm not sure that this is good advice. The essential measurement is the distance between the two planes of sprocket teeth centres. The thickness of the plate making up the sprocket may or may not be equal to half this distance, and of course even if it is the additional sprocket he may be using is not guaranteed to be of equal thickness. Further compounding this is that it also depends on the sprocket-tooth-plane being centred across the thickness of the rings (or at least identically offset), which is not always the case.
Perhaps better is to measure the spacing his crankset uses between the existing rings and arrange spacers such that that is what he gets to the third.