Considering the regular hatchback can comfortably fit a 18x9.5 with offsets between +38 and +45 on a 255/35r18 tire, I would think the GRC with additional 20-30mm widened fenders per side should be able to fit 10.5" wide wheels, assuming inner clearance to the strut is similar to the normal hatchback. I'm estimating the GRC will end up having similar fitments to the EVO X, with max square fitments in the 18x10.5 +22 range. For 18x10.5 fitments, tires will likely range from 265/35r18 for an easy fit to 295/30r18 for max thicc fitment with additional camber and rolled fenders. With that said, I predict the most popular sizes will still be 18x9.5 +15 to +22 range with a 265/35r18 tire for a balanced daily/track setup.TE37 / Advan GT/ RPF1-SBC
Curious about what wheel size the GRC can fit. Think 18x9.5 is out of the question?