KNUCKLE UP

Story & Photos by Tom Morr
Superlift's 8-inch kit lets late-model Chevys step up to 37's
Photo

The Superlift 8-inch kit (#K922) comes complete with knuckles, full-width control-arm crossmembers, a diff skidplate, new shocks and struts, billet CV spacers, bumpstop relocators, kicker braces, and rear blocks with add-a-leafs. An application is also available for 2007-current 2WD half-ton Chevys/GMCs.

IFS lift kits that use replacement knuckles are significantly simpler than the time-proven “bracket” kits. Properly engineered replacement knuckles retain stock-spec steering geometry without having to relocate the linkage. In contrast, bracket kits require additional components to correct steering angles. These additional parts require more installation time.
Design-wise, clearances present challenges for knuckle kit engineers. The knuckle has to be profiled so that it maintains proper geometry while clearing wheel and chassis parts during lock-to-lock steering and suspension cycling. Fitting tall, 8-inch lift knuckles takes some skill. Incorrect knuckle designs can prematurely trigger the Electronic Stability Control (ESC), directly affecting how and when the ABS system is engaged.
Superlift has manufactured GM IFS 4x4 lifts since shortly after these vehicles were introduced in 1988. The company uses advanced 3D CAD software combined with the automakers" engineering data to design its kits. This permits all design aspects of the platform to be virtually tested and approved before protoype parts are manufactured for real-world verification. Further, Superlift final-machines its knuckles in-house and manufactures all its brackets and spacers on-site. This minimizes the hope-that-it"s-right quality-control approach used by overseas manufacturers.
Previous-generation GM 4x4s used torsion-bar IFS. For 2007-current 1/2-tons, the factory upgraded to a coilover front design (GMT900 platform). Ride and handling are improved, as is ground clearance.
Superlift"s 2007-current K1500 8-inch kit (#K922) uses replacement extended-length gas-charged front struts, which install with supplied “hat” spacers. The replacement struts utilize the factory coils. Spring-swapping is safely accomplished by using a commercial strut-compressor tool.
Another notable feature is that this Superlift 8-inch kit doesn"t require front-diff modifications. Differential ear-cutting often comes with the territory during Chevy IFS lifts, but Superlift"s relocation brackets are engineered to keep the OE diff housing intact. The driver"s side rear lower control-arm mount has to be notched so that the diff can be lowered and reclocked to gain proper CV axle and front driveshaft angles. Billet CV axle spacers are included to compensate for the increased distance between the diff and the kit"s replacement knuckles.
Other minor tweaks to OE components: When transferring the OE front wheel-bearing assemblies to the new knuckles, the dirt shields must be trimmed slightly for clearance. Tie-rods must also be shortened and re-threaded using the included 16mm die nut; this allows the OE tie-rod ends to be retained.
For durability, Superlift uses 0.25-inch thick laser cut plate steel for all load-bearing brackets. The front full width lower control-arm crossmembers are tied together with a differential skidplate. Kicker braces made from DOM tubing add extra stoutness between the Superlift crossmember assembly and the factory transmission X-member.
To level the rear, Superlift"s base kit offers cost-effective 5-inch-tall spacer blocks and full-length add-a-leafs. Extended-length Superide twin-tube hydraulic shocks are included. This setup retains many of the factory ride, hauling, and axlewrap characteristics. Optional replacement 6-inch leafpacks with 2-inch blocks are available for customers who want even better ride quality and/or don"t like the look of tall rear blocks. Superlift"s testing revealed that axlewrap generally isn"t a problem in current-model K1500s.
Refer to the photos and captions for more details about the Superlift K1500 8-inch lift kit.


Superlift"s replacement ductile-iron knuckles are engineered to clear the wheels and chassis parts with minimal track-width increase. Tie-rod bosses are positioned for proper steering geometry; final-machining is done in-house.

1. The instruction sheet gives precise directions for notching the factory crossmember and lower control arm. This allows the differential to be relocated without modifications to its housing.

2. The kit"s brackets lower the differential to maintain proper driveshaft and axle angles. The factory front driveshaft can be retained.

3. Lift is accomplished by relocating the lower control arms 8 inches below their stock mounting points. Factory swaybar links are repositioned on the lower control arms using a template provided in the instructions.

4. The existing coil springs are swapped onto the premium Superlift gas-charged struts. A commercial strut compressor vise makes the job safe.

5. Billet spacers bolt between the CV axles and differential. This provides proper spline engagement at the knuckles.

6. Front details include swaybar lowering brackets and corrective parts for brake hoses, ABS and ECS. The OE tie-rods are trimmed and rethreaded, allowing full, ECS-compatible, steering.

7. Made from DOM tubing, the kit"s kicker braces provide “extra credit” between the Superlift crossmember cradle and the factory transmission x-member.

8. “Base” rear components are 5-inch blocks with full-length add-a-leafs; 6-inch replacement springs with 2-inch block are optional. Kit components reposition the brake lines and bumpstops. Rear shocks are included.

9. Chevy/GMC wheelwells must be trimmed this amount front and rear or 37s will rub. The Superlift system clears 35s without these modifications.


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