I tried and tried to find a reference that listed cratridge BB sizes. I thought it would be nice to know the distance from the right face that bottoms out against the frame to both the left and right spindle ends. That way you could campare BBs and figure out what you needed. You could even move the crank arms a known distance. Alas I have never found such a thing. I think the advice about the LBS is your best bet when unsure. You can walk in with an old BB and line it up right next to the new one to make sure it is what you want.