Originally Posted by
xtc800
I knew this was a Trekking crankset (hence the "T" in T551), but when I looked at all the drawings and the current BB setup, I couldn't find any reason that it shouldn't work. I did have to change out the front derailleur to accommodate the change in the chainring tooth counts, but obviously that has no bearing on the installation of the crankset (with respect to the fixing bolt). I was hoping I was just forgetting to do something that was obvious. If you have any other ideas, I appreciate your help.
If your bottom bracket has spacers on both sides, you have to measure bottom bracket shell width to the outside of the spacers since they effectively widen your bottom bracket shell. A normal configuration if your old crank was made for a 73mm bottom bracket and was installed on a 68 mm bottom bracket would be 2 spacers on the drive side and one on the non drive side. If your new crank is made for 68 mm bottom brackets you have 2 remove 2 spacers to compensate for the shorter spindle on the new crank, usually one on each side