I am undecided as to filling the rear tires on my 2305. I went as far as to get a valve but haven't decided yet. I mow about 50% of the time and don't have any steep slopes or banks that I use the tractor on. I have a ballast box for FEL work. The only time I think I need extra weight is when using the rear blade. Could someone give me a little input as to your thoughts?