Total Newb here....and I apologize in advance if this is the wrong place for this post.

Purchased an 07' JKU X in May....great deal and the vin check was kosher. Now I'm modding it up, working on performance related issues before I explore off road wheelin' since this is my DD. Just about where I want to be and saving up for the wheels and tires. IMHO I think that the 34-35" tires "look" like they fit the body of the unlimited that has a lift. I'm running 265/70R17 currently and they just seem too small.

I have a couple of Jeeper friends and I'm getting mixed reviews on the Largest tires I can run on an X with the stock Dana 30 fronts and the Dana 44 rear axles. Like I said, this is my DD but I do plan on doing some off road wheelin'....but nothing too hard core. One of my buddies is telling me that my stock axles are doomed if I run anything larger than 33's off road and that I'm just asking to get stranded with a busted axle shaft if I go any larger. This is definantly gonna be a factor in which size tire I ultimately decide to purchase. Can anyone give me some info about this subject? Any experiences or technical facts.... Do I have to beef up my front and rear axles before I pull the trigger?

Another quick question....anyone know how the 34-35's affect the mpg and performance of a JKU X?

Thanks....and I must say I am really greatful for this site...it has helped me out of a lot of bad choices equipment wise and has some great walk throughs on upgrades!

You guys are GREAT!

 

I wouldnt worried about ur rear just yet, but the front dana 30 is a different story. But dont worry!!! All you need are some sleeve and C gussets which may run you no more then $250 and maybe another $150 to get then welded in.

And dont worry about your alxe shaft, as long as u dont have lockers. With an open diff you really cant broke shafts.

 

Several guys on here are running 37" on the X D30. If you don't abuse it.It should be fine.

 

With your automatic tranny, the general consensus is 5.13 gears make a good fit. The problem is that's getting to be a pretty small pinion gear--easier to break. That doesn't mean plenty of folks aren't running that combo successfully--they certainly are. As suggested, get C-gussets and axle sleeves to beef things up. Drive it easy and you'll probably enjoy a long relationship with your 35s.

 

I am running 37's on stock 30 axles and 4.10 gears with no upgrades to them. Haven't had an issue yet.

If you are worried do the upgrades others have suggested and just be cautious where you wheel and dont put yourself into a situation where axle breakage is certain to happen and you will be fine.

 

D30 on 38's, 5.13's, stock shafts, Rusty's Truss kit, and another companies 'C' Gusset's. No issues. Few pics of walking up "Juggernaut Hill" this past weekend so you can see what I put it though.

 

I ran 35s and stock axles with zero issues on my 08 X. Heck I ran 36 TSLs on my old yj w a 30 in the front bone stock for 2 years.

Now I dont play on rocks, just trails and mud.

 

straight up beast mode...