I have a #2 Tiller mounted on a 1250 that I purchased about 5 years ago. I put new OEM belts on at that time. I used the tiller for 2 seasons and it broke the main belt on the third season, probably put less than 20 hours on the belts. I didn't use it for a couple years and am trying to figure out why it's breaking the belts so I can use it again. OEM belt isn't available anymore so I purchased a 17/32" x 146.5" Gates Blade Runner belt and installed it. I placed a piece of cardboard under the mule drive and started the PTO. I immediately can see small rubber bits flying off the belt and dropping onto the cardboard. I cannot figure out why, the belt isn't rubbing mule drive pulleys are positioned straight back to the angle gearbox. Here are some pictures of what I'm working with. Notice the front edge of the belt on the PTO pulley is wearing down. I put some mule drive pulleys on that are narrower than the ones in the picture, belt rides flush with the edges of them. That didn't make a difference.