Originally Posted by
breezwhey
Long story short, has anyone ever run, or know for sure if you can run a Stronglight 99 crankset double with a 40T or 42T outer chainring and a 30T or 32T inside chainring? In other words, use what is normally the inner chainring as the outer? I don't know why it wouldn't work, since the on the 99, the outer chainrings use the same 86 BCD to mount as the inner, but there may be something I'm not considering. I realize there are many other alternatives, but this is my cheapest solution to my problem.
As
bikemig points out, Spa Cycles sells 86 BCD chainrings. That includes 40/42T outers and 30/32T inners, so you don't even have to think about using an inner as an outer:
https://www.spacycles.co.uk/m2b0s149...l-40-50t-outer 
(But even if you swapped rings between inner and outer, it ought to work fine. Not having the counterbore on the outer face just means the head of the crank bolt will sit proud of the chainring. EDIT: I wouldn't flip a ring around to use the counterbores, for the potential issues John calls out in following posts.)