B 1000

You will hate the freeway, but will love the punch from a dead stop. Though I am assuming, as there is no way in hell I'd go 5.13s with 35s in a 2012

KCCO JK

I'm running 5.13s on my 2012 2dr (manual), and I love it. Yes, the rpms are a bit higher, but unless I'm gunning it, I usually don't go above 3k. Mpg depends on what i'm doing, and how fast.. But at 70mph, on flat highway, I average 17-17.5 mpg. City drops that a bit, but i'd say, on average, that I'm getting around 14.5-15 mpg(city + hwy combined), even with all the mountains and hills in southern california. Personally I bet I could go to 4.88s and still be happy, but I intend to get 37s after my current set of tires die off, so hopefully i'll be exactly where I want to be after that.

Mopar2Ya

I rarely drive on the highway, & my tires are 325/60 that actually measure 35". Don't some 37's(labeled) actually measure 35-36"?
Thanks, it's been hard to find anyone w/a 3.6 that has 5.13's. You don't feel that the rpms are to high at 70mph(bad for the engine)?

B 1000

[QUOTE] I rarely drive on the highway, & my tires are 325/60 that actually measure 35". Don't some 37's(labeled) actually measure 35-36"? [QUOTE]

Yes. In fact almost all tires run smaller than advertised. Some worse than others. KM2s and Duratracs run small, Toyos and MTRs run tall, but none true to their advertised size. Hence why when people ask what tire to buy to get a true 35" the best answer is a 37"


[QUOTE]Thanks, it's been hard to find anyone w/a 3.6 that has 5.13's. You don't feel that the rpms are to high at 70mph(bad for the engine)?[QUOTE]

I can't speak personally, but I imagine it would be. Hell my 4.10s on 34" tires puts me at 2500 RPM at 70 (speed/distance double checked through GPS) so I imagine 5.13s would put you at 3k or so?.... Hell 75-80mph must be brutal

Sorry, I don't know how to quote multiple people in one post

BubbaJK2012

Was wondering on the charts if it is true tire size or manufacturer size to go by!!

KCCO JK

At 70mph, I'm sitting at about 2.8-2.9k which although it is higher, isn't really that bad. There is a chart floating around that has 5.13's on 35s is the highest of the blue scale, which makes a "fair" DD. And as for whether to be concerned if it's bad for engine life.. I'd personally be more concerned about running in a lower gear, at higher rpms, to make up for the fact that the axle gearing is inadequate.. Because that will commonly have you around 4-5k, especially when going up hill. That, and it's only 1k outside of the "green bar" on the tachometer.. Nothing to be worried at.

At about 80, I'm sitting at about 3.2-3.3k. Not too shabby all considered. The pentastar, despite how common the "head" issue, is a fantastic engine. The rpms don't get really shady until about 90.

Mopar2Ya

The "+ button at the lower right corner.
I was told it's actual measurement.
Good info, all the threads about gearing on the interwebs has my head spinning, most say the 5.13 is way to low for the 3.6 & ~35" tires. I'm thinking 5.13, the roads I travel are 65mph & under.

Tankerbell

I've talked to a couple local shops (in CO) about this and they have all said that going 4.88 on 37s with the 2012 pentastar is the way to go. 5.13 ratio would probably be too high. 35s would be good with the 4.56 ratio. Personally I find all this gearing stuff confusing especially since I do a good amount of mountain highway driving at high altitude...when I upgrade to 35s I'm going to have a tough time deciding between the 4.56 and the 4.88 (although a supercharger could make everything easier). Personally, I think I am going to go 4.88 with the 35s especially if I plan to upgrade to 37s at some point...

Mopar2Ya

Yeah, most say that 5.13's are too low for the 3.6, but I have talked w/a few 3.6 owners who have 4.88's w/35's(not measured) & say they wish they'd gone 5.13.

Tankerbell

Haha now I have to start researching all over again!