Hey I'm new to the fourm, just got a 2013 JKU auto with 3.21 gears and I got a great deal on 35' Red Letter Grabbers. I know I have to lift it first but I would like to hear from anyone running 35's with this setup (3.6L/auto/3.21)?

 

I have a 2013 JKU, 6 speed manual, and 3.21s. My JKU is in the shop now getting regeared to 4.56 and I only have 33x12.5r15 Duratracs. It's nt bad, but it's noticeably slower than my wife's JK and I have to downshift on the highway more. I can't maintain 6th in any kind of incline. Add in we normally have 5-6 people in the Jeep, gear, and will potentially tow a small military type trailer in the future new gears were a no brainer.

I think 35s and 3.21s it's a must to regear as soon as you can afford it. Especially if your tires are heavy, which being 35s they are probably LT rated and very heavy.

Some will tell you that you can get by, but probably not for long especially if you wheel or live in/near hills.


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I have a 2013 2dr sport with 3.21's and I'm also looking into putting on 35's. I'm going to get the 35's no matter what. I'm just having trouble deciding on which tires to get. There are so many options available.

 

I have a 2012 Sahara with auto and 3.21s. It's ok in the city, but trying to hold 70-75 on the hwy in 5th is damn near impossible. Throw in a 15-20 head wind and 4th becomes a challenge.

I'm going with 4.10s because it is my daily driver and 4.56 is too much gear for my use. I live in flat Florida. 35" KM2s with 4.10s will put you dead at 70 with 2500rpms. Ideal for me.

4.10s are more expensive. It sucks.

 

You can get 4.10's cheap from a 2007-2008 jk...

just searched all of craigslist and found this:

Jeep Wrangler JK 4.10 Gears

 

It is certainly doable. I live in a very hilly area and don't have too many problems with running my 315/75r16 Duratracs. It won't win any races, but it isn't unbearable either as my daily driver. If the RPM's are screaming up on a hill, just back off for a millisecond or so and it will up shift. If you are the slightest bit of an aggressive driver I wouldn't do it. I rarely, if ever, get above 70mph so i cant really comment on "high speed" performance. I have no intentions of running the 3.21's long term, but I am not in a hurry to do it until I can afford to do lockers at the same time.

 

My 2012 has the same set up. 35" Maxxis Bighorn M/T. I have not driven it set up yet because I'm in Afghanistan still. My says she has not noticed any power loss. We use an AEV ProCal to reset the speedo. She is in Jefferson County Missouri where it is very hilly. She is know speed demon on the highway either. She said it is running great and not struggling at all. I trust her to be able to tell the difference. This is our second JK. But like i said I haven't driven it since the mods were done.

 

I'm running 35s on my 3.21s with a six speed. It sucks but I'm saving for 4.88s. It can be done but just expect a significant loss in torque and power

 

I mean, you'll be ok for a little while but def start saving for 4.56's.

 

I had 35's on my 2010 2 door and after a month or so I had to swap over to my 33's because the gas mileage was so bad. 3.21 gears on the highway with 35's i was getting about 13-14mpg, I started to use the 35's for offroading only which was perfect in 4lo