The last time I was at the track with my bone stock 05 Magnum RT it went 14:47 @ 97.17 mph. It crosses the line about 4500 in third and I felt like it was geared too tall overall. The magnum has 2.82 rear end gears, and I believe 3rd gear has a 1.4:1 ratio. Currently my car has stock size 225/60/18 dunlop tires on the factory RT rims.

I can get a deal on a used set of plain steel 17" STX rims with 245/45/17 BFG tires; if my math is right their smaller diameter would get me about 5000 in 3rd across the finish line. I figured a rear wheel swap at the track would be a cheap and easy way to gear the car down, as an expariment, to see if it helps lower my ET.

But then I heard using different diameter front to rear wheels/tires on the LX cars will throw a trouble code, so the only way to do it is to use a diablo predator (which I don't have yet) to adjust the computer for new tire diameter. Do any of you guys with Challenger/Magnum/Charger have any experience with this?

In the same vein, someone suggested if my car is already spinning the tires off the line (which it does) that going to lower gearing by changing gear ratio or tire diameter would only make that problem worse and I won't be any quicker. Again, do any of you guys who have LX cars have any experience with this?

I plan on going to the track wednesday night, but I don't want to waste money on 245/45/17 rear tires and rims if it isn't going to make me any quicker and might even throw my stock computer into a spazm.

Thanks in advance for the advice!