I believe that the factory wheels on a Pioneer have different offsets front to back. If this is similar to a rhino you can order the rims with the correct offsets to make them run true (in the same track). Does anyone know if this will work for the pioneer as well? I am looking at going with bighorns...most likely 26s or 27s. Once I get it home I can do some measuring but I am anxious to start ordering parts!
Just remember the wheel width is going to give you different numbers. In the 12 inch wheels companies like ITP run 7 inch wheels front and back while others will use a 7/8 inch combo. Most of the 14's you will find the 7/8 combo also. The factory wheels are different widths so you will get different "numbers" there also.
All your finding is the center line of the wheel which should be the same on the front and rear of the machine. It will just depend on the wheel width as to what numbers you will have.