With 3.21s and 35s you are going to burn up the clutch pretty quick but it can be done. 6th gear is out of the question, and 5th gear becomes your OD gear. Shouldn't be the big fuel mileage hit that you would see on an automatic, and you'll likely be about 20% better than the auto.

 

I just put 35s (315/70R17) Duratracs on my 6sp 2dr with 3.21s. I've only been driving it for a little over a week. My long term gas mileage (computer) was 20-21 (combined country and small city driving - no highway, no rush hour). It's been 18.5 since I reset it the day I put on the tires but colder weather plays a part in that too. 6th gear is not "gone" but is only good for flat or slight downhill at 50+ mph. I find that I run in 4th more often, less in 5th (i.e. 35-40 mph in 4th instead of 5th). Taking off in 1st is noticeably different so I'm sure it's a little harder on the clutch. I will probably regear in the future but feel like I can run as is for quite awhile.

Bear in mind that I have a 2 dr. Your experience will undoubtedly be different in an Unlimited with the extra weight and longer wheelbase.

 

The aero drag at 60+ mph is where 6th is going to be tough if not impossible. It makes up a huge percentage of the power you need to keep a JK rolling. The weight and rolling resistance drag increases with velocity in a linear fashion while aero drag increases exponentially. By the time you reach 70mph more than 80% of the power made is being used to cope with aero drag. At 50mph it's only about 70%.

 

Ahh... that makes sense. I almost never even hit 60. I guess it all comes down to the type of driving you do. I know I would like 4.88s better!

 

Get 35's you will deeply regret getting 33's the moment you see a jeep on 35's. I regreted getting my 33's about two weeks after I got them.

 

Seattle hills are doable....although I had 35's / auto / 3.73's before I regeared. Get yourself a Superchip. With my superchip tune and O/D off on 3.73's w/ 35's, I had more power and get-up-and-go then I did stock with 32's.

 

OD off gets you 40% more rpm at cruise speeds which more than makes up for less than a 10% increase in tire size. Off road is quite different story.

 

good deal yes, but add that to a 8 hour round trip drive to Lunatic in DALLAS, and 2 tanks of gas and it becomes not so sweet of a deal...

Just because 2 guys are in TX doesn't mean they are close it's not like your pissant northeaster states J?K

 

My clutch is fine. I have not smelled burned clutch on a vehicle of mine since I was 16.

 

You don't need to smell burning clutch to be using it up. At idle the vehicle is ready to roll at 6mph and some level of clutch control needs to be applied until you reach that speed. It also 50% more mph than what the standard recommendation for 35s with a manual transmission, meaning that with the appropriate gear set less clutch control needs executed.