Hey guys, I currently have a 3.73 posi 10 bolt rear end in my camaro, and am running 245/45/17 all the way around. I plan on changing to a 275/40/18 or a 275/35/18 rear. I’m getting confused as to what size tire this 3.73 ratio is based on? obviously changing tire height will affect the rear ratio, and Knowing this will help me determine how much of a change my new tires will make to my ring and pinion. Is there any easy way to figure this out ? I’m assuming the 3.73 ratio is based on some generic tire size? Any help is appreciated!