As always, Sheldon Brown's pages cover this subject comprehensively. However, all road BBs are 68mm and this BSA thread form is the norm, your frame isn't Italian or French which are the other threadforms sometimes found. You don't say what Cannondale you have but assuming it is a road frame then all should fit. Easiest thing for peace of mind is to measure the width of the BB between the two faces. Some MTBs have a 73mm BB.