I have a clone and had trouble finding tires for the rear in the size 255X50X16. Tire Rack didn't have them. Finally found a local tire store that ordered them in for me. Brand is Mirada. I never heard of them, but here is some info. I have Cooper tires in front, 246X50X16. MultiMile Mirada Sport GTX Tires from Tire Factory
There are very few makers of that size. My Dad, just put some BF Goodrich on his. The only two available when he was looking locally were the BF's and some Falkens.