I have 2004 G coupe with OEM wheels. Current tire size is 245-40-18 rears. I happen to have 2 tires from another car. Size: 255-40-18. Would these tires fit my rear OEM wheels without any issues? If anyone has tried this size or wider than this size, please give me suggestions on the fitment or any other issues. Thanks.

 

They will definitely fit. Depending on the tire brand and the actual size of the tire, there is a chance that your VDC system might act a bit fishy if it throws the rotations per minute out of whack enough from the rear tires against that of the fronts and also side to side while cornering.

 

They should work but like Partyman mentioned ^ if there isn't to much bulge and you have clearance! You posted 255/50 at the top and 255/40, which is it?
Gary