It was a problem long before 2004. The B2150 which came out in 1988 lacked room under the rear fenders for chains (well, reasonable room unless you wanted to tear things up.) I would bet there are other Kubota models before that with the same problem. And essentially none of them had any way to widen the rear tread other than spacers.Not unless something has changed... serious Kubota, this has been a problem since the L2800 in 2004. Are you going to change anything???