I went down to one of dealers in the area that currently has an R/T with the 20" wheels. I was very disappointed. The rims simply look cheesy and don't match the muscular vibe of the body. I wanted 20 inch wheels because that's what the SRT has but there is a major difference between the SRT rims and the 20" rims offered for the R/T. I wish Dodge would offer the SRT package, rims, breaks and hood stripe for the R/T. Someone mentioned the SRT also sits about an inch lower. The trim level on the SRT just fits the body style so well, I hope there's a way to get that same vibe from R/T. I have not seen an R/T with 18" wheels yet so I'm still evaluating .

 

I also hate the shiny cheap plastic 20" covers on the R/T. From what I understand though, the gear ratio is only different on the manuals. I believe the gear ratio is the same for the automatics for both the 18 and 20. I do prefer the 20" wheels though because it fills in the wheel well a lot better. I will likely get the 18"'s and replace with aftermarket replica srt aluminum rims, or just wait for the SRT rims to show up on ebay. If you order the rims from dodge, they are almost $900 each (from what I understand).

 

Besides the sidewall causing a "stiffer" ride feel, 20's on an auto R/T offer no performance gains. You still only get a 3.06 rear gear on the auto, not other gear choices are even optional from the factory.

On a 6spd, however, 20's with the Trak Pak net you an increase from 3.72 gears (standard on the 6 spd cars) to 3.92 gears as well as a limited slip diff (not an option on any auto or on the 6 spd with 18's) and the traction control off button will really turn the traction control all the way off. The traction control on any auto or 6spd with 18's will still be on slightly even in the off postion, probably to overcome the fact that you can't get a limited slip in these other configurations.

The 20's are also a tad wider, for possibly a little more grip.

I was thinking 18s and an auto, just as a second car my wife could drive and to keep initial and maintanence costs down (read-tires!). But after I found out about the gears, limited slip and traction control, I talked her into the 6spd (I already know she can drive stick, she had a 94 Mustgang GT with 5 spd manual) and 20's with the trak-pak. Now it is just a waiting game to find one on a lot so we don't have to special order one.

 

I like the look of the 18's and the 20's...however I am finding you do not have near the tire selection for the 20's. I think overall, if you are going to drive the car alot, 18's would be the way to go.

 

I agree with Tony,
No real choices with the 20 inch wheels. I am looking for 18's, and Richmond now makes 3:55, and 3:23 gears for the SRT8.

 

Andre... any idea how the 3.06 gears of the auto"s gearing stack up against the 3.92 gears of the six speed"s gearing overall..??

Thanks Bro...

 

I ordered my Car with 18" but one showed up down the street with 20" and I had a hard time buying it cuz I really wanted to 18"s
in the end I canceled my order and bought the 20"er one and planned on putting 18's on it still.
But I must say after the first week of driving it, I loved the 20's and when I see a 18" R/T I think it doesn't have near the impact at all when they roll up or sit next to mine.

go 20 if you can, but I'd suggest dropping it 1" so it looks closer to the SRT

 

The Limited Slip rear comes with the 18's as well. It's on my window sticker. I also prefer the look of the 18's and my Challenger is a daily driver. You cannot beat the ride from the Michelins. The car has a great ride when you want to be comfortable and cruise which for me is the majority of the time.

 

The all season Good Year I have as a option on my R/T 245/45/20 are only $122.00 at Tire Rack . Depend's on what you buy I guess. I put a set of 245/50/18 Yokohama Advan S4 on my wife's car ( 300C ) for around $1000.00 plus mount and bal. She love's them and they ride good . I have the 6 speed stick with 3.92 in my R/T . MPG so far 18 to 23 at 1200 miles . I think my car ride's great and everyone that has ridden with me .