RE: 2009 R/T axle ratio
I check Tirerack for specs. Goodyear F1 P245/45/20 28.7" overall diameter optional tire comes on car
Pirelli Scorpion P245/45/20 28.6
Goodyear Eagle RS-A P235/55/18 28.0
Michelin Pilots HX P235/55/18 28.4 overall diameter standard tire comes on car
Not much of a difference .3 of an inch.