A friend of mine has 20s on his Avalanche but his tire size is only 275/45R20. He's needing new tires and was wanting to get something bigger. I told him that I would find out what the best size is for 20s. He was looking at the 275/55R20 and I recommended the 285/50 but when I checked the tire calculator the 285/50's height was a little shorter than the stock 265/70/17. The calculator showed that the 295/50/20 is the exact size. Does anyone make this size. How about the 305/50/20? Would that be too big.