I ran 7-10 on the turf tamers and 15-20 on the Marshall groved radials, both on normal(non reinforced) rims. The only time I had one blow off was when running about 5 lbs in a rear turf tamer.
ERIC

 

I run 6lbs in my rear tamers. 14lbs in my radials. Since the radials are rated for highway use, I wasn't sure on running lower pressure like other ATV tires, or 32lbs like on-highway vehicles, so I just split the difference.