I just went through this on my O4 fs3000, I ordered some 16" WW rims and they were on backorder, I found that 225/75/16E LT tires were the ticket and still are within load capacity. I has maxxis 8008's but after 4 years had one blow. I had great luck with the Westlake tires that came on the trailer when I bought it, turns out they now have the same nylon cap as the maxxis, I bought my 6 here on ebay http://www.ebay.com/itm/6-ST-225-75R15-WESTLAKE-RADIAL-TIRES-10-P-R-NEW-TRAILER-SIX-TIRE-SET-/291578074332?hash=item43e36854dc&vxp=mtr
my tires came and two days later my new 16" rims showed up that were 2 months backordered.....so maybe next year I will do the swap. The ebay deal is smokin, free shipping, no sales tax (unless your in GA)