275 might be a tad big fo the 8.5 rim. most manufacturers recomend 9inch wheels. the middle of the tire might bulge and therfore not give you full contact with the road. in other words, less grip with big tire and small wheel. the better deal would be 265, but the tire selection is nonexistant in 20 inch and cost of one is through the roof. better would be 9 inch wheel with a 275 if one could fit one in there. keep your eyes on the contact area and see if middle is getting used a lot more versus the outside and inside/edges of a tire. please post up pics as they sit on car, i am very inteested in this topic.