the HIVE by e*thirteen has been producing a 30mm AL spindle crankset that fits English threaded BB (bottom bracket) shells in both 68 and 73mm in widths. Yup, you heard it right, you can safely install a cutting edge superlight N stiff 30mm aluminum integrated spindle crankset onto any old frame! Like those old steel 70's "10-speed" bikes you find in decrepid, rotting public junkyards...or Bike Pirates - same thing, right? :D Just kidding Geoffy B (Bike Pirates founder)!
Albeit, currently that I know of, the only 30mm diameter aluminum spindle crankset available that wld work here is e thirteen's own fifteen G cranksets which r an MTB 4 bolt 104 bcd design. Maybe a BB30 triple? It's all about the BB shell+bearing width in relation to the crank's integrated spindle length; spindle must be the right length/long enough/longer than a typical road, double chainring crankset's BB30 spindle.
This (useful?) technical/mechanical discovery brought to you by BIKEFX by Dex....or just, Dex...that's my name and cycling's my game!