A friend I partner with on some larger jobs has a 52" LZ HP with a 23hp Kohler. He only gets about 200 hours out of his hydro drive belt before they shred and break. The new belts seem to run very smoothly, no vibration, good pulley alignment, etc. I have heard some comments as to lack of a bearing on the idler pulley being a cause for this, but with only 400 hours on his machine I can't imagine the bushing being worn out........it doesn't seem to have excessive play in it. Any suggestions?