Thanks for all the info, my situation is the tractor i bought has 21.5-16.1 turf tires on a one piece rim. I'm looking for a less expensive option then buying 4 new rims with centers from the dealer. The more I look into this, and contact aftermarket distributors it seems that the 5425 and maybe the whole 5025 series being a (narrow) series has an oddball rim and center combination. I was just hoping someone may have come across a similar situation. There are centers on ebay with 8 holes and 8" from bolt to bolt through the middle of the 6" center which is what my tractor measures. It lists several tractors but not mine, so I contacted the the seller (my tractor parts) and they checked with there tech department and said they will not fit. I just want to know if some of these aftermarket options will work and are they not cross referencing because of a slight difference, which may not make a difference. Thanks