I've just (finally) taken possession of the long awaited Gazelle Champion Mondial cross bike. Just a quick question : the rear der. is Nuovo Gran Sport, bottom jockey wheel has the well-known pointed teeth look, but it's the top one that puzzles me; completely smooth! I can imagine the teeth being worn and pointed, but no teeth at all??? Surely there should be something left UNLESS it's supposed to look like that (which I doubt). Ideas?