Well, an E60 is only a 225/60x15 , a G60 is a 255/60 and an L60 is 275/60, so by going to 26x10 and 28x12, you're stepping over the factory dimensions in width anyway. PLus, the 275 width on a 7" rim is going to ull it in a skosh more than an equivilent 8" rim would. So if you want to duplicate the factory sizes in metric, you'd need the afore mentioned sizes. In the SR line, they may be closer to 26x8 front and 28x10 rear. Here is where I found my conversions at ;
http://www.tirerack.com/tires/tiretech/45_conversionchart.htmlIf you just want to go bigger, then the options open up, but each car is a little bit different with the factory assembly tolerances and I've heard Cudas actually have smaller wheel wells than Challengers. This also highlights how rim offsets, tire diameters, and aspect ratios can work together or against a plan. I can fit the 26x10 on my car with just about .75" clearence in any direction. Other have managed to stuff 275/40x17 in the same space, but it just shows how the sidewall height and wheel backspace have to corresponding to the space inside each fender. Have you actually got under there with a tape or are you just comparing tire specs on the web?
FWIW, 235/60x15 front and 295/50, both on a 8" rim under my challenger. They had enough room to move around and up and down
Here is the MT SR 26x10 front on an 8" rim and 26x12 rear on a 10" rims. I was concerned enough with fit to pull the t-bar so I could completely cycle the suspension and turn lock to lock. I've since lowered it a tad more in front
