Does anyone know the diff between the FC-7700 and the FC-7701?
Is one the triple?
i asked the same question a few months back.
from what i was told, the 7701 is forged, while the 7700 is… uh… something else 
bottom line was the only difference was the manufacturing process (according to the replies i received here anyway).
No. 7703 was the triple. I think it may just have been a design change.
The original 7700 crank was made in 2 pieces to get the hollow arm. the outer part of the crankarm was forged in 3 dimensions, and a flat plate was welded to the back of the arm and then machined smooth.
I think the 7701 crankarms were made as one piece. No welding required
jason k is correct.
The 7700 were made with a 3 piece and welding process. The 7701 were made with the “new and improved” one piece forging process. Both compatible with the 7700 BB.
As previous posters have mentioned. The one piece hollow forging was perfected after the Hollow Tech process was started by “cut and pasting” The one piece units are about 25 grams lighter.
-SD