I was wondering if this makes sense; the GRX FDs are designed to work only with GRX crank sets due to the 2.5 increase in chain line. Could this FD work with Shimano 2x MTB cranksets since they have a longer spindle for 73mm bb?
Sure looks like it. The Shimano specs for road (130) triples was 45mm chainline and MTB (135/142) triples was 47.5mm chainline. So that extra 2.5mm chainline in GRX sure looks like a move to a MTB or 135/142 chainline.
