We pulled apart the front of a 76 (disk brake Cruiser) and found that one of the birfields was starting to crack in 4 places and probably would have broke on the next trail run. We have a set of birfields out of what was said to be 76 but the measurement from the bell out to the end of the splines is shorter by like a 1/2". Both of them have the same number of splines and the length is the only differance we can find. Will they work or what is the deal? Any help would be greatly appreciated.