I have a 2011 JKU Rubicon 4-Door with 2.5" rancho Sport lift kit installed w/ 33" Tires using the stock control arms and regeared to 4.88:1 w/ stock drivelines. I'm thinking about going up to 37" and has been considering to upgrade my stock control arms (all fours) to the adjustable (short) ones w/ 4" coil springs to be daily driven and of course a trail rig (No hardcore rock crawling stuff) . My question is:

Is it possible just to replace the coil springs and control arms instead ( all 4's - upper and lower to get the right geometry back).
Do i need to replace my front and rear driveline and get a new set of trackbars ? and
Do i need to replace or just beef-up my current stock Dana 44s axles or remain stock for this purpose?
A little help from all you good buddies will always be highly appreciated.
My apologies if there's already a thread posted previously for this concern. Thanks!

 

There are a couple of threads about 37's on d30 and d44 non Rubicons...

your gearing should be fine for 37's, I have 5.13, but I looked at the chart and leaned towards better for off-road, which was 5.13, but just one step away was good off-road but better on road, and that was the 4.88's

you will need something like the AEV Procal to adjust your tire size, but you probably used something to tell the Jeep's computer that you regeared, yes?

you might want to replace your drive shafts...depends on how you drive it...Mall Crawl or rock garden crawl!

matthew

 

You can simply add coils and arms and it would allow you to adjust caster and pinion angles. You will not be able to regain factory geometry.
You will need longer sway bar links.
You will want to address steering and will likley need a drag link flip and a 4" raised rear track bar bracket on the axle.
At some point your driveshafts will fail, the more off roading you do will lots of droop the quicker they will fail.
I would recommend at least doing the C gussets. Many will recommend doing a truss or sleeves as well.
I would recommend upgrading to a cromoly rear axle shaft.

I would disregaurd the advise that Matthew has given since he has a different motor and transmission combonation then you do.

What motor and transmission do you have?

I would recommend that you read this thread as well.
https://www.jk-forum.com/forums/modi...-lifts-288269/

 

Dirtman, I always like to check your posts as I find them to be informative and useful, where did I err?

4.88 used with the 3.8 minivan engine? I do tend to forget that the majority of the JK's out there have that engine...

Matthew

 

The 07-11 automatics have a terriable gear ratio in them where a 33" tires should be at 4.88 gearing to compare to a 4.10 on a 6 speed. If the op does have the 3.8 with auto he should be running 5.38 gearing.
JK models outside of North America are offered in Diesel motor as well. No knowing the motor the op has will make the difference.

 

Agreed I have a 2011 auto with 4.88 and just 35s and wish mine was geared a little lower. Still better than the stock 3.73 it was a nightmare.

 

I find my 4.88's adequate but im rolling a supercharger too. My jeep hardly works now.

Staying away from a supercharger, 5.13 or 5.38's is probably a good plan.

 

Thanks for the input Matthew. Yes, I did some adjustment using the AEV Procal after going to the 33" tires and rims plus the regearing to 4.88's. I guess replacing the drive shafts will be my next upgrade.

 

Thanks a Lot for the valuable info Dirtman. I will take it into consideration most especially the steering modification and the reinforcement of my axles plus matthew's advise regarding driveline upgrades. Whew! I'm gonna take it one at a time for budget is the Biggest Obstacle for the 37" upgrade. Thank you so much guys!

 

Oh and By the way, I still have the stock motor V6 gas w/ air intake upgrades. Still learning the ropes!