Originally Posted by
Kuromori
There's enough of a gap between the teeth of the granny and the outer tabs/bolts for the chain to sit? Or is the spacing basically equivalent to running a triple outer and granny with no middle, resulting in a large tooth-to-tooth spacing between rings?
Here's the way I see it. Approximating 4mm tabs and 8mm chainring spacing, and using the outer teeth as a reference of 0mm chainline:
0mm - Outer teeth
-2 to -6mm - Spider tab
-8mm - Normal double inner, this is only 2mm away from the tab, so the chain will hit the tab
-12mm to -16mm - Granny position on a triple, 12mm is for standoffs that need additional spacers. There are 8-12mm between chainrings, so there's a large risk of skating or the chain actually going between the rings.
I believe the spacing will be fine--- but it will depend on the crank set.
As I mentioned, in my case, this was the only 130BCD I could easily pull off the shelf and attempt to run the triplizer as the outer ring and effectively move the 74BCD granny to be in the space occupied by a traditional inner. I believe if my crank arm did not have the platform for mounting a 74BCD chainring, this set-up would work perfectly. I wish I had an unmounted Shimano 130BCD to attempt this on. I'm pretty certain it would work on this Dura Ace crank.
However, I'm not planning to pull it off the bike to service the BB until after Christmas, so it would be a long wait for the OP to get an answer. I'd like to encourage @
Byepsycho to try his Willow set up in a similar way on his Centurian crankset.
Again, just a boomer's two cents FWIIW for a millennial. YMMV. 