The owner's manual for my '19 T4R says 83 ft lb for steel wheels and 76 ft lb for aluminum wheels. I found those specs listed in both the "changing a flat tire" section and vehicle specifications section. It doesn't differentiate between the different styles or sizes of aluminum wheels so I assume it is for all (17" and 20"). My guess is it has more to do with the type of lug nuts used (steel - tapered acorn, aluminum - mag flat washer) than size of the wheel.