Seems like all of the 34" tires are getting about impossible to get.  I need 8 20.8-34's but have only found one place that had any used ones and they weren't enough better than what I've got to go to the effort to swap them.  I have been watching for another tractor that used this size, but haven't found any sets that were in decent shape.  I've talked to a lot of the big tire dealers in the midwest and they all told me that I'm not going to find anything used unless I just stumble across them and then I'll have to get lucky and be the first guy to stumble across them.  I don't suppose you could switch sizes and rims and be any money ahead?  I looked into changing to 30.5-32 singles instead of the dualled 20.8-34's but by the time I bought the tires and rims, it wasn't going to be cheaper than 8 new 20.8's.  The worst part is, none of the dealers I talked to could give me a time frame on actually coming up with 8 of the same tire in my size.

Good Luck,

Mike