The Control Arm Trap: Why Your New Lift Kit Won't Fit Your GMC Sierra
Share
You finally saved up the money to put a massive 6-inch suspension lift on your 2014–2018 GMC Sierra 1500. You want the ultimate towering stance, so you order a premium kit, clear your weekend, and put the truck up on jack stands in your garage.
You tear the entire front suspension apart. You grab the massive, heavy-duty lifted steering knuckle out of the box and try to slide the ball joint from your upper control arm into the taper. It completely bottoms out, and the nut won't thread on. The hole in the knuckle is the wrong size. You check the lower control arm, and it’s completely wrong, too.
Your truck is entirely dismantled, and the lift kit you ordered is physically impossible to install.
You just fell directly into the Control Arm Trap.
During the K2XX generation, General Motors was highly inconsistent on the assembly line. From 2014 to 2018, they shipped trucks with three entirely different types of factory control arms: Cast Steel, Aluminum, and Stamped Steel. Each of these arms uses a completely different ball joint size. Because a full lift kit replaces the steering knuckle, if you order a kit engineered for Cast Steel but your truck has Aluminum arms, the parts will never fit.
You don't have to return your massive freight boxes; you just need to inspect your suspension before hitting the checkout button.
In this guide, we explain exactly how to use a simple magnet to identify your Sierra's specific factory control arms. We'll show you why a true 6-inch lift requires cutting your frame, why you probably can't run your factory wheels, and how to safely tower over the trail.
Compare Premium Lift Kit Upgrades
No Fine Print Armor, Heavy-Duty Value, or Complete Packages?
|
Lift Kit Series |
Top Brands |
Tech / Build |
Best For |
|
High Clearance Lift |
BDS Suspension |
1/4-Inch Steel & FOX. |
Hardcore Abuse & Peace of Mind. The absolute pinnacle of K2XX lifts. Features massive 1/4-inch steel crossmembers, heavy-duty skid plates, and premium FOX 2.0 or 2.5 shocks. Backed by their legendary "No Fine Print" warranty: if you break it, they replace it. |
|
Heavy Duty Lift System |
Zone Offroad |
Ductile Iron Knuckles. |
The Ultimate Value. Engineered by the same parent company as BDS. Zone delivers massive strength utilizing CNC-machined ductile iron steering knuckles and laser-cut steel crossmembers, giving you premium suspension geometry without the premium price tag. |
|
Complete Lift Kit |
Rough Country |
N3 / Vertex Shocks. |
The Street & Trail Hybrid. The most popular kit on the market. Provides everything you need in one box, including heavy-duty lifted knuckles, fabricated lift blocks, and your choice of their nitrogen-charged N3 daily-driver shocks or massive adjustable Vertex coil-overs. |
Frequently Asked Questions (Lift Kits)
Can I keep my factory wheels if I install a 6-inch lift kit?
Usually no, due to backspacing issues.
When you install a 4-inch or 6-inch lift, you replace the factory steering knuckles with massive, heavy-duty lifted knuckles. Factory GMC wheels sit very deep inside the wheel well (high positive offset / large backspacing). If you try to bolt factory wheels back on, the inside of the tire will physically crash into the new knuckle. You must either run aftermarket wheels with 4.5" to 5" of backspacing or install high-quality billet wheel spacers.
How much does it cost to have a shop install a lift kit?
Expect to pay for 8 to 12 hours of labor.
Installing a full suspension lift is not a simple Saturday driveway project. It requires supporting the engine, dropping the entire front differential, cutting the steel frame, and compressing springs. Most reputable 4x4 shops will charge between $1,000 and $1,800 for the installation, plus the mandatory post-lift alignment.
Will lifting my Sierra 6 inches destroy my gas mileage?
Yes, expect a noticeable drop.
The lift kit itself adds a few hundred pounds of heavy-duty steel, but the real MPG killer is the massive 35-inch mud tires you will bolt on. Pushing a taller, wider, heavier truck through the air requires significantly more energy. Expect your fuel economy to drop by 2 to 4 MPG depending on your final tire size and whether or not you re-gear your axles.
Tower over the trail. Clear the 35s.
Ditch the fender rubbing and reconstruct your suspension geometry with massive, heavy-duty crossmembers and dropped differentials. Shop our verified collection of premium 2014–2018 GMC Sierra 1500 Lift Kits.