Rear wheels are 15x10 with 5" backspace and the fronts 15x8 with a 4.5 backspace. I was just checking out the Mickey Thompson website and looking at the sportsman s/r radials. They seem to have some sizes that will replace my discontinued tires well. Here are my current tire specs and what they have avaiable.
Front
BFG 265-50-15 25.5 Height/8.6 Tread Width/10.9 Section Width
MT S/R 26x10x15 26.1 Height/8.8 Tread Width/10.3 Section Width

Rear
BFG 305-50-15 27.1 Height/10.3 Tread Width/12.1 Section Width
MT S/R 28X12X15 28.0 Height/10.4 Tread Width/12.1 Section Width

http://www.mickeythompsontires.com/street.php?item=SportsmanSR