Cognito 2.5-Inch Lift Kit | 2024+ 2500HD AT4X/ZR2

Cognito 2.5” Leveling Lift Kit – 2024+ AT4X / ZR2 2500HD

Overview

The 2024+ GMC Sierra 2500HD AT4X and Chevrolet Silverado 2500HD ZR2 mark GM’s first heavy-duty off-road models, factory-equipped with an advertised 1.5” suspension lift.
Our independent measurements tell a different story — the front sits 2.5"–3" higher, while the rear lift is accurately 1.5”.

Rather than a true lift, the front suspension functions more like a factory leveling kit, paired with a 1.5” rear lift block.

Front Suspension Design

Unlike traditional lift kits with taller subframes and knuckles, GM achieved the added height through redesigned components:

New lower control arm with revised torsion bar clocking

Adjusted bump stop positioning

.2” longer upper and lower control arms to maintain factory track width

Modified steering knuckle neck, while retaining OEM geometry

This setup achieves a leveled stance but introduces some travel and wear limitations.

Factory Limitations

While the AT4X/ZR2 gains front up-travel, it loses about 1” (35%) of droop travel, leaving only 2-1/8” total. This reduction can cause front shock top-out over dips or large bumps.

Additionally, the added height accelerates wear on the pitman and idler arms.
We strongly recommend adding the Cognito Pitman and Idler Arm Support Kit (sold separately) — a patented solution for this common issue.

Cognito Standard Lift Kit Solution

Cognito’s Standard Lift Kit is designed to correct these shortcomings, enhancing ride quality, geometry, and long-term durability.

Kit Features:

Adds 2.5” front lift and 0.5” rear lift

Increases front droop travel to 3” (Cognito’s minimum standard)

Retains OEM Multimatic DSSV shocks

Includes billet extended front shock clevis mounts

Maintains proper CV axle angles with differential drop brackets

Keeps torsion bars tucked in the frame using Non-Torsion Drop Brackets

Rear lift achieved by replacing the 1.5” block with a 2” block and longer U-bolts

For maximum suspension performance, upgrade to one of our premium packages featuring Cognito control arms and performance shock options.

Tire & Wheel Fitment Guide

Stock tire or 35x12.5 tire on stock wheel
This will look small in our opinion, 12.5 wide tire might need 1/4" wheel spacer.

37x12.50 tire on stock wheel
Will require a wheel spacer at least 1/4” thick. A 1.5” wheel spacer looks really good. Use tie back kit plus medium trimming.

35 on 10” wide wheel +18mm offset
Use tie back kit plus medium trimming.

35 on 10” wide wheel, 0mm offset
Use tie back kit plus medium trimming.

37x12.50, 9” wide wheel +18mm offset
Use tie back kit plus medium trimming.

37x12.50, 9” wide wheel, 0mm offset
Use tie back kit plus heavy trimming.

37x12.50 on 10” wide wheel, 0mm offset
Use tie back kit plus excessive trimming. Might have an occasional rub.

Note: OEM AEV Edition SALTA wheels fit up to 37x12.5 tires. Non-AEV wheel fitment is currently being tested.

Vehicle Fitment

2024–2025 GMC Sierra 2500HD AT4X

2024–2025 Chevrolet Silverado 2500HD ZR2

Warranty & Manufacturing

Limited Lifetime Warranty – applies to all Cognito-branded products.
Proudly Made in the USA – engineered and manufactured in Southern California.