As stated above, the sprocket teeth allocate the frame spacing. The takeup spool drive in the camera has a slip clutch to allow for the increased diameter of the film spool as you wind more film layers on it. If the grease is hardened on your old pre-war Contax, then it can literally drag the film farther than it is supposed to, as you get towards the end of the film and most of it is on the takeup spool. So, you get frames farther and father apart as you get towards the end of the frame.
This is a problem with your camera, not the takeup spool.
If this is happening to you, it needs to see Henry Scherer.