Still waiting for my all weather stockers to wear out but have been looking at Bridgestone RE-71Rs in 255/40R18 (265/40R18 does not seem to exist). Another contender popped up at the Rack, the Yokohama AO52 in 265/40R18 with a pretty scary looking tread.
Main criteria is dry gription, in a square setup but no crazy treadwear less than 100 R compound tires. Don't care: Noise, Winter driving, treadwear. Less care: MPWh efficiency. I know just going to "extreme" summer tires will reduce range and extra width will cause even more road friction and wind resistance.
Stock: 235/45R18: +Efficiency. -Rim protection. -Less Grip.
Bigger: 255/40R18: +More Grip +Rim protection. -Wrong diameter (-1.1%).
Biggest: 265/40R18: +More Grip ++Rim protection. -Suspension Clearance -"Out of spec" wheel width (8.5" vs 9" min).
Likely tires: RE-71R, AO52, Michelin Pilot Sport 4S.
From what I have read, the AO52 are RE-71R "grade" tires, 4S are a step down. 235 and 255 width are safe for clearance 265 is getting close. The Aero 8.5" rims are not approved for 265, but its not too extreme. Wondering if the -1.1% size difference for 255 is much of a concern. Anybody running the bigger sizes?