Originally Posted by noobinsf

Saint Sheldon's chainline reference is here: https://www.sheldonbrown.com/chainline.html

Does your current setup measure 43.5mm from the midpoint between the two front rings to the middle of the bottom bracket shell?

Going to a triple would mean you need to measure 45mm between the middle chainring to the middle of the bottom bracket shell, and to get the bottom bracket that works with your selected crank to achieve this.

My guess is that when you swapped from the original BB to the sealed unit you have now, you went from an asymmetrical spindle (longer on the drive side) to a symmetrical, and that brought the crankset inboard a little bit. Again, just a guess.