I have a Great Dane Chariot 52" with 25 hp Kohler. The main belt from the engine to the deck seems to develop cracks quickly. Eventually the belt frays and snaps. The mower only has 170 hrs on it. This will be the third belt that we will put on it. Of course the dealer says no warranty on belts. Has anyone else had a problem or can anyone give advice on what is causing this.