ReadyLIFT 1.75" Leveling Kit with UCAs | 2019–2025 GMC Sierra AT4 & Chevy Silverado Trail Boss

ReadyLIFT 1.75" Leveling Kit with UCAs | 2019–2025 GMC Sierra AT4 & Chevy Silverado Trail Boss

Is This for You?
You're running a 2019–2025 GMC Sierra 1500 AT4 or Chevy Silverado 1500 Trail Boss — trucks that come from the factory with a 2" front lift and longer strut assemblies — and every generic leveling kit on the market either binds the factory ball joint or contacts the lower strut and CV axle assembly. You need a leveling kit engineered specifically for the AT4 and Trail Boss platform that works with the factory suspension lift, not against it. The ReadyLIFT 66-3921 delivers 1.75" of additional front leveling lift with CNC-machined billet aluminum strut spacers and DOM steel UCAs with corrected geometry — purpose-built for this platform.

The Result
CNC-machined aircraft-grade billet aluminum top and bottom mount strut spacers deliver 1.75" of front leveling lift that works in concert with the factory 2" lift — providing the required amount of lift without conflicting with factory strut geometry or clearances. Heavy-duty DOM tube steel upper control arms with corrected ball joint cup angles, 1-ton heavy-duty replaceable ball joints, and ReadyLIFT TCT (Terrain Control Technology) maintenance-free pivot bushings with side-biter washers restore proper suspension geometry and improve alignment retention at the new ride height. Trail Boss trucks clear a 295/65R20 on a 20x9 0-offset wheel; AT4 trucks clear a 275/60R20 on the same spec — fender opening design differs between the two models.

Verified Fitment (OFAS Standard)
✅ Fits: 2019–2025 GMC Sierra 1500 AT4
✅ Fits: 2019–2025 Chevrolet Silverado 1500 Trail Boss
❌ Does NOT fit: GMC Sierra 1500 AT4X
❌ Does NOT fit: Chevrolet Silverado 1500 ZR2
❌ Note: AT4 and Trail Boss have different front fender opening designs — maximum tire size differs between the two models; test fit before finalizing tire selection

Wheel & Tire Fitment

AT4 and Trail Boss have different front fender opening designs — do not assume the same tire size fits both models. ReadyLIFT wheel and tire fitment recommendations are based on Wheel Pros wheels and Nitto tires. Actual dimensions vary meaningfully by manufacturer — overall diameter, tread width, aspect ratio, and sidewall construction will differ. Every tire and wheel combination must be test fit prior to final installation. Upgrading to heavier 10-ply (Load Range E) all-terrain or mud-terrain tires will noticeably increase suspension stiffness and alter ride harshness compared to factory 6-ply (Load Range C) tires. Consult your local installer for application-specific guidance.

Installation & Engineering Notes
This is a bolt-on leveling kit requiring no cutting or welding. UCA hardware must be torqued to specification at ride height. A professional 4-wheel alignment is mandatory post-installation to verify torque specs and lock in corrected geometry. Lifting your vehicle raises its center of gravity; exercise appropriate caution on- and off-road. All Advanced Driver Assistance Systems (ADAS) including GM Safety Alert Seat, Lane Keep Assist, Forward Collision Alert, and automatic headlight leveling must be checked and recalibrated after installation.

Engineering Question: Is your truck a GMC Sierra AT4 or Chevy Silverado Trail Boss, and what is your model year? AT4 and Trail Boss have different fender opening sizes that affect maximum tire fitment — confirm your specific trim before selecting your tire and wheel combination.