I had written the following in my first post:
"It'll be easy to customize the inner ring with something aftermarket even, but the outer ring attaches to the inside of the spider, so it should ideally be made for the middle position of a 110/74mm triple, TA make all sizes up to 46 teeth for that position, but Sugino might be the only source for anything larger."
But I've since changed my mind about this. If you're using a 110mm inner ring, then you could use an outer ring that was made for the outer position of a compact crank (110mm BCD), which means LOADS of options. It is only if you use the 74mm BCD for the inner ring that you would have to worry about the outer, and as I said, you'd then need to use an outer ring designed for the middle position of a 110/74 triple crank, which limits you to 46-teeth. Even so, you probably don't want anything bigger than 46 teeth if your only other ring is a 74mm BCD (32 teeth or less). Therefore, this is not the disadvantage that I originally thought it was.
In case anyone is wondering, the difference between rings made for the outer position and those made for the inner/middle position is the countersinking of the bolt holes - outer rings are countersunk on the outside and not on the inside. So if you mount an outer ring inside the spider (as on this crank) then the bolts will not be flush with the ring, they will instead stick out, and the chain will probably then rub on the bolts when the chain is at certain angles. However, if your inner ring is attached to the same bolts as the outer then this cannot be a problem, which is the case on this crank when using a 110mm BCD inner ring, but not when using a 74mm BCD inner.
Sorry to cause some confusion, please carry on admiring this pretty and ingenious crank.
Last edited by Chris_W; 09-01-10 at 11:32 AM.