TheDirtman

The principals still apply but a long arm will be somewhat custom and you will be able to correct some things you can't with a bolt on kit. The new brackets will change the geometry of the suspension and different companies will do different mounting locations so it will vary from manufacturer to manufacturer. You might ask if who you are buying from can give you the mounting locations so you can plug it into a 4 link calculator to see how it lines up.

ABENDX

And the disappointment is going to start to set in.

Tomsryt

Thankk you Dirtman, it's always a pleasure to read a mature and intelligent bit of advice.
I learned something.

jadmt

So with all this great information (thanks Thedirtman and Planman) what would be considered a decent RTI number for a mild JKU build? What would be the lowest acceptable rti number for say doing something like fins and things in Moab?

planman

You can do Fins and Things or Hell's Revenge with a completely stock jeep. It is better if the front swaybar is disconnected. You'd bypass some of the obstacles on Hell's Revenge with a stock jeep.

You can do Moab Rim with a JKU on 32" or taller tires with the swaybar disconnected--without lockers.

A JKU 2.5" lift with flat flares and 35" tires, with stock length front bumpstops and 2" rear bumpstops, with 10" travel shocks, can do 90% of the trails and obstacles in Moab--even without lockers. With lockers, the jeep could do 95%.

Some of the more interesting obstacles and trails require larger tires, lockers, and a risk of body damage.

I haven't RTId many JKUs. So, I couldn't tell you a number.

However, if you run 10-12" travel shocks with bumpstopping/brakelines/fender clearance/links that allow for the full travel of the shocks, and run 35s or larger tires with lockers, your JKU will be capable of more than you are likely willing to attempt.

InvictusVeritas

I have a 2013 JKU and until reading this post, most if not all other posts I have read had me believing that I MUST go get a lift kit and all of these other ancillary items to compensate for the "side effects" that come with the lift.

This should be a MUST read prior to any mods!

I have been on what I think we're some great trails at Uwharrie and up at Brown Mtn. in NC with my current ALL stock JKU sport and got through everything just fine.

The biggest worry I have had has been clearance. That crunching when the front makes it over the obstacle and the mid section hits the top of that "hill/bump" in the road or what I think I have seen referenced as Camel backs. That crunch for a newbie is nerve racking.

Now to my question, sorry if you already answered and maybe I just didn't understand.

If I want to run 35s on my stock JKU so that I can get more clearance from the ground, what's the absolute necessary additions necessary or stock components that need to be changed out?

Gears? Fenders? Shocks? Springs? Just to name the items I've been reading about.

Thank you in advance!

Rafa

DunnyBunny

Well I have seen stock vehicles run with trimmed factory fenders and wheel spacers and they say they have no issues. Those are the necessity. I would put a leveling kit at least just to help in the front

InvictusVeritas

If I Understand correctly, it's the tires that are going to give me the ground clearance. Modifying or changing fender to give clearance necessary for new tires along with spacers. Then If I determine I need or can/will use added benefits from suspension lift, than I Can start to change out components like springs and shocks and all the othe supporting members of the suspension system, but that leads into a "this" is connected to "that" and the snowball of mods begins.

Also as I begin to weigh vehicle down with Steel Brawler Rockers from PSC and new bumpers, and winch and such, new or more capable springs and shocks start to come into play.

WHAT ABOUT GEARS? (Not yelling, more for emphasis)

I read a posting about the new tire size and revolutions necessary to drive the tires and how the engine works harder, engine performance drops, and MPG drops.

So do I need new gears if I do the 35s because I want the ground clearance?

Also, how much clearance am I really going to gain with 35s over what I believe are 31" stock tires? I'm guesstimating somewhere between 1.5 to 2 inches. Is this correct?

Also, what about this Tummy Tuck stuff I'm reading about, where does this play in in the clearance equation?

Again, THANK YOU in advance, the help is much appreciated!

Rafa

GJeep

See gearing table (post 18) at --With steel bumpers etc', and loaded for camping/overlanding, + 3 or 4 people on board , my '12 JKU with 4.1 gearing has plenty of power for everything but the most extreme offroading (which I don't do, as the Jeep is still quite new).

As you can see in the table, 4.56 is also recommended, giving about 11% more power and the same percentage increase in r.p.m. .
4.88 or 5.13 gearing are for extreme rock crawling and the toughest obstacles, but such gearing would be less practical on roads.
The added diameter from 31" to 35" is 4". As only half of it is below the axle, you gain 2" lift.
The 35" is not necessarily the true diameter, and the calculation should based on the actual size of the specific tire.
My 35"s, for instance (315/70/17) are actually 34", so, vs a (true) 31", the diameter increase is 3", and the gain is 1.5".

That was for tires which are inflated for roads, say 30 psi.
However, offroad, you'd deflate to 20 psi or less, so the tires sag, and the ground clearance is actually lower than the calculation.
Adding weight by mods and load (e.g. recovery gear, water, fuel, camping), plus airing down, may reduce ground clearance by at least 1".

TheDirtman

Your gear ratio is very important to look at, while with the new motor and 3.73 gears people seem good with 35's, a 4.10 would be a better ratio over the 3.73 but I would not spend the money for such a small increase in ratio. Where you live and where you drive will have a big difference as well. If the terrain is flat and you drive a lot at highway speeds then you will be happier with 4.10 vs 4.56 but if you live in the hills and spend most of your time in city driving or lower speeds the performance gear set would be better.

Off road you will really notice a big difference with a performance gear ratio if you have the standard transfer case. Those with the 4.10 can run much better with an everyday gear ratio due to the extra step down in the transfer case.

All in all you should be looking at what is best for you as a daily driver and not get sucked into the whole "you need big tires and a big lift because you have a jeep" due to the fact you off road a couple times a year on dirt trails.

The JKU is a long vehicle and drags the belly, that is what it does. It really is a piss poor off road vehicle due to the wheelbase and overall length. Its better then a full size pick up but not by much. Protecting the belly and learning how to properly pick your lines will make you a better driver in the long run then just jacking the jeep up and throwing it at an obstacle, I will guarantee that there will always be a more challenging trail somewhere that is going to do damage to your rig no matter how much you build it. When the trail get too easy due to your building you get bored and try harder stuff, that is just how it is.