Just spoke with the manufacturer and he broke out his dusty old book on rim sizes. I guess this is the one that all tire manufactures use as their bible. Apparently, my rim measuring 5.25" from bead to bead is the exact correct rim for those STA Traxion tires. He admitted that he will be running down to the engineers to fix their website and catalog which lists the correct rim width as 6".
I finally feel better. Now to order those babies!
