1.75″ front leveling lift for 2019-2023 GM AT4 and Trail Boss Not compatible with Sierra AT4X or Silverado ZR2 Edition.

Includes DOM tube steel upper control arms with TCT maintenance-free pivot bushings and 1-ton ball joints CNC machined aircraft-grade billet aluminum top and bottom strut spacers AT4

– AT4 – Max tire 275/60-20, 20×9 0 offset wheel

– Trail Boss – Max tire 295/65-20, 20×9 0 offset wheel

If re-using factory wheels on a Trail Boss, you can run max tire size 285/75R18 with NO trimming!

ReadyLIFT customers have asked for it and we have delivered. In fall of 2018 we announced our new leveling and SST lift kit offerings for the all-new GM 1500 trucks. We specifically did not include the factory lift kit-equipped GMC AT4 and Chevy Silverado Trail Boss. The AT4/Trail Boss are factory equipped with a 2″ front lift. This front lift includes a longer front shock/strut assembly. When combining a traditional leveling kit on these factory lifted trucks, several issues present themselves including binding problems with the factory control arm ball joint and contact concerns with the lower strut/CV axle assembly.

The ReadyLIFT 66-3921 1.75″ leveling kit is similar to our popular 66-3086 leveling kit for pre-2019 trucks. The 66-3921 leveling kit provides required amount of lift without causing conflict with the factory strut geometry and clearances. In light of the factory upper control arm’s lack of dynamic range when the AT4/Trail Boss truck is further lifted, this leveling kit includes our popular tubular upper control arms with corrected ball joint cup angles, heavy-duty replaceable ball joints and out new Terrain Control Technology (TCT) maintenance-free pivot bushings with side-biter washers to improve alignment retention.

Note: AT4 and Trail Boss do not fit the same size tire. This is due to the difference in front fender opening design. NOTE: Not compatible with Sierra AT4X or Silverado ZR2 Edition. 66-3921 Leveling Kit: AT4 – Max tire 275/60-20, 20×9 0 offset wheel Trail Boss – Max tire 295/65-20, 20×9 0 offset wheel

Note: AT4 and Trail Boss do not fit the same size tire. This is due to the difference in front fender opening design.

66-3921 Leveling Kit:

AT4 – Max tire 275/60-20, 20×9 0 offset wheel

Trail Boss – Max tire 295/65-20, 20×9 0 offset wheel

If re-using factory wheels on a Trail Boss, you can run max tire size 285/75R18 with NO trimming!

Tire Size Note: ReadyLIFT wheel and tire fitment recommendations are typically based on Wheel Pros wheels and Nitto tires. Due to product differences among tire manufacturers, tire specifications and dimensions including, but limited to, overall diameter, rolling diameter, tread width, aspect ratio, lug pattern, sidewall construction and inflation pressure, will vary meaningfully by tire and wheel manufacturer. Every tire and wheel combination should be test fit prior to installation. Consult your local installer to learn more about the right tire fitment for your application.

Ride Quality Note: When lifting a vehicle and installing aftermarket wheels and tires, a tire manufacturer’s construction and material quality can alter vehicle ride quality. When increasing a vehicle wheel and tire size, most larger aftermarket truck and SUV tires are 10-ply (or more) E tires compared to typical OEM 6-ply C tires. This more rigid sidewall construction increases the perception of suspension stiffness often described as ride harshness. The ride, handling, traction, noise, fuel economy, and wear differences between All-Season, All-Terrain, Mud-Terrain, or Trail-Terrain type tires can be significant. Please take into account tire and wheel choice will generally have a meaningful impact on the ride & handling experience.