I'm sure it's a combination of things. The original BB was 112mm with the original crankset. I've got the feeling that Shimano really wanted me to use one of it's FD's with its crankset. The centerline was on the third cog from the top before I swapped out the BB instead of the centre cog. Like I said, everything worked on the stand but not while riding. Shifting the chainrings 2.5mm to the left seems to have made all the difference. Al