I just picked up a 2007 Sierra 2500 LMM for work/daily. I'm trying to decide between buying a Cognito Upper Control Arm kit or a full 4 inch lift kit from Cognito. The UCA kit will allow the correct ball joint angles when cranking up the torsion bars which usually results in 2-3 inches of lift. The 4 inch lift kit should keep both the upper and lower control arms at factory angles when set @ 4 inches of lift. I'm wanting to put somewhere between a 33"-35" tire but my MAIN concern would be ride quality. I've heard from others that on the UCA kit, the control arms will sometimes bottom out causing a rough ride but wanted to see if anyone else had experience with either of these kits. Thanks.

 

Guess nobody over here lifts their 8-lug trucks. Lol

 

33s- UCA kit
35s- 4" kit

just depends on what size tires you want to run.
your going to want to beef up that front end if you want to run 35s.
rare parts tie rods, cognito idler/ pitman braces and some nicer shocks...

 

I have a 6" on my LMM and plan on putting the UCA just to improve ride quality.

 

UCA improve ride quality and you can clear 35s with just a leveling kit. I would recomend the uca with the leveling kit tho for the ball joint relocation and they allow longer travel for your front shocks so they don't bottom out as much.

 

I have the uca kit on my truck and I love it. It doesn't affect the ride that much either

 

I would stay away from any and all level key type lift. A Cognito full lift will also lower the front diff the corresponding amount too, keeping your CVs flat. It is significantly more money, but do the 4" NTBD kit. Good CV angles, good ball joint angles, good tie rod angles. Plus upgrade to better Fox or Bilstein shocks, and it will drive like a dream. Another plus is the full kit from cognito also comes with the idler and pitman braces in the kit.

Dream kit for a 2001-2010 2500HD:

4-6" Cognito NTBD Lift (with braces)-set at 4"
Deaver full rear springs
Sulastic Shackles
Fox or Bilstien shocks.

Will ride like a dream. But aint cheap.