I hit a sweet spot of brakeless, 28t, freecoaster, 165mm cranks.
But I'm slowly going back. All 3 bikes have a rear brake again (necessary), I opted for a 25t on my latest build and I prefer it, and I just now swapped out the FC wheel for a cassette.
I feel like I'm reversing into shop bought spec again. Except I'll always stick with 165mm crank arms now.
The Fly frame just flat out does not have enough clearance for a 28t. I bought a chunky Primo BB for it and I've run it with that + 28t sprocket for a couple of years of hard industrial daily riding.
But, I always get crank issues. No matter what crankset I fit, I get issues. Niggly ones.
Looking at it, the offset between sprocket and driver is very extreme. It has to be though, because the 28t inly barely clears the frame.
So I figure that has to be a contributor. A constant side stress on the drivetrain putting forces onto the sprocket.
So that's going back to stock Fly 19mm 8 spline cranks with a Trebol 25t sprocket.
See how that goes.
by Awkward_Importance49