The 31 spline is the stouter of the axleshafts with a 1.31-inch diameter versus the 28 spline’s 1.29-inch diameter. ... but swaps over to an 8-lug wheel pattern on factory axle flanges.

Going up from the 1LT, the 2LT, SS, and RS Camaros come with 8-inch-wide front wheels and 9-inch-wide rears, which allows for a much wider rear tire (275 mm compared to 245 found on the LS and 1LT ...

For example, if the original stock tire size is 215/65R17 and you buy 18-inch wheels, the right tire size for the larger rims might be 225/55R18, with the differences being the larger-diameter ...