Choosing Shocks for Your 2019-2021 Chevrolet Silverado Trail Boss / GMC Sierra 1500 AT4

GM took these upgrades further with the introduction of the Trail Boss and AT4 Packages. Chevrolet did offer a Trail Boss package in 2016 but that was short lived and only offered for 1 year before being discontinued. With the new Trail Boss and AT4 packages, GM gave customers a 2” lift in the front and a 1” lift in the rear supported by Rancho monotube struts and shocks tuned specifically to GM’s specifications, higher angle CV axles to accommodate the extra lift and factory 275/65 R18 tires.

Factory Suspension Basics

  • 2” factory lift over the Non Trail Boss and AT4 models
  • GM specced Rancho Monotube
  • 2” lift strut 1” Rear Block
  • Come with 275/65 R18

Existing lift system being replaced by aftermarket options, stacking lifts, upper arms.

Aftermarket Suspension Options


However, if you are looking to step up the ride quality both on and off road with a capable suspension setup to handle the larger bumps and washboard roads, the Bilstein 6112’s and their 2.6” diameter shock paired with the 5160 reservoir shocks in the rear will handle those tasks and are the perfect setup some people looking into getting into more serious off roading.

Bilstein - 5100 Series, 46mm Piston

Daily Driver, Off-Road


One of the best selling shocks for the Truck, SUV, and Jeep market, the Bilstein 5100 excels at daily drivability mixed with off-road capability. Slightly firmer than the 4600 series, and firmer than a stock-like shock, these high-pressure gas shocks offer improved handling on lifted vehicles and improved response with larger wheels & tires.


  • Leveling-Kit ability for certain apps
  • Great off-road capable shock upgrade
  • Durable, long lasting
  • Improved handling on & off-road
  • Heavy Duty, Tow, Haul capable


  • Firmer than stock-like shocks
  • Performance Shock, higher price

Bilstein - 6112 Series, 60mm Piston

Daily Driver, Off-Road


A new addition to Bilstein’s arsenal, the 6112 shock is equipped with a massive 60mm active piston and 2.6” shock body, providing exceptional off-road capability and handling. This shock is aimed solely at the adventurer, offroader, and overlander that sees a lot of dirt, but also doesn’t want to sacrifice daily driver comfort.


  • Leveling Height Adjustments
  • 60mm piston, “best in class”
  • Price-to-Shock ratio through the roof, 2.6” shock & spring less expensive than 2” coilovers
  • Massive off-road ride upgrade, improved road handling and comfort
  • Long lasting, durable, serviceable


  • Does not come pre-assembled from Bilstein
  • Requires coil-spring compressor for installation


Fox took this a step further with the new addition of their Performance Elite 2.5 series. With the Performance Elite line of Fox shocks you are getting a CNC machined 2.5” diameter body along with reservoirs and Fox’s Dual Speed Compression (DSC) adjusters. With the DSC adjusters, you are able to adjust the high speed compression and the low speed compression independently to really dial in the ride quality for the specific terrain that you are going through on any given trip. Your low speed compression will be your slower shocks shaft movements (body roll, brake diving, g-outs at the transition of a sand dune) while the high speed compression adjustments allow you to tune for the faster shock shaft movements (washboard roads, potholes).

FOX - 2.0 Performance IFP

Daily Driver, Off-Road


The Fox 2.0 IFP high performance shocks are for a go-fast attitude offroad, providing significant handling improvement on & off-road over typical street-shocks. These shocks excel in aggressive terrain and the dirt, and are a great performance upgrade over factory or Bilstein.


  • Coilovers provide Leveling-kit ability
  • Excellent High Performance entry level shock
  • Handles hard hits well
  • Improves handling and traction in all terrains
  • Rebuildable / Serviceable


  • Higher price point compared to similar offerings
  • Requires servicing for optimal performance
  • Firmer than factory and other factory-like upgrades

FOX - 2.5 Factory Series

Off-Road, Tow/Haul


Stepping up to the Fox 2.5 Factory Race series shocks brings significant improvements in both comfort and ride control. The increased size of the 2.5” shock offers increased shock oil, lower operating pressures, and allows high speed driving on aggressive terrain while maintaining great control of the vehicle through race-level tuning.


  • Huge improvement to road comfort and off-road handling in one package
  • Adjustable & Reservoir options
  • Serviceable, Rebuildable, Custom Tuning Available
  • Excellent handling in high speed environments


  • Requires servicing between 30-50k miles for optimum performance

Icon Vehicle Dynamics

Icons Stage 2 kit features a 2.5 series extended travel non reservoir coilover for the front and 2.0 series rear shocks. Stepping up to the Stage 3 system, you will get the same coilovers in the front, but with the added reservoir and the rear shocks get upgraded to 2.5 series shocks with piggyback reservoirs. Now if adjustability is what you are after, look at the Stage 4 system. With the Stage 4 system you get Icons tried and true CDCV valve. This is going to be your mid range compression adjuster offering 10 levels of adjustment to get you dialed in for any street or dirt driving you plan on doing.

ICON - Stage 1 Coilovers

Daily Driver, Off-Road


Step into improved handling and comfort for your daily drive and dirt activities. Through ICON’s digressive valving, this leads to improved handling without sacrificing too much ride comfort in the pursuit of spirited driving and high performance.


  • Improved handling on and off-road
  • Built for moderate to high speed
  • Rebuildable and serviceable
  • Can upgrade through higher stages


  • Requires servicing for optimum performance
  • Off-road focused, may be too firm for daily-driver only


King has both 2.5” and 3” coilover and shock options for the Trail Boss and AT4. The 2.5 series are a great upgrade and will handle everything most of us can dish out to them, but if you are the type that likes to get rowdy out in the dirt and drive faster than our abilities can handle, the 3.0’s are going to be what you want to look at. The massive 3” piston allows for more damping force to help soak up all the rough stuff. To match up the front 3” coilovers, King has come out with a 3” internal bypass smooth body shock with the compression adjusters that you would find on the front.

King - 2.5 OEM Performance Series

Off-Road, Tow/Haul


King’s tried and true offroad shocks for your application are unmatched in ride comfort and performance, offering legendary tuning out of the box. These shocks really excel in high speed environments and aggressive terrain, for serious off-road enthusiasts.


  • One of the highest performing shocks available for OE apps
  • Serviceable, Rebuildable, Custom Tuning Available
  • Compression adjustment and reservoir options
  • Badass Blue color


  • Lacking on features from competitors
  • Requires servicing between 30-50k miles for optimum performance

Frequently Asked Questions

Whats the big differences between the Trail Boss and AT4 models compared to base Silverados and Sierras? Can the suspensions be shared?

The biggest difference between the Trail Boss/AT4 and the base models is going to be the suspension. The Trail Boss/AT4 came from the factory with a 2” lift in the front and 1” in the rear. Bilstein is the only manufacturer that has specific part numbers for the Trail Boss/AT4. Fox, King and Icon share the same part numbers for the Trail Boss/AT4 and the base models.

How much can I lift the front of the truck before I need UCAs? Do I need new UCAs when I do a leveling kit on my Silverado/Sierra?

In terms of alignment, we find that anything over 2.5” of lift will require an aftermarket upper control arm. With that said, any coilover capable of 2.5” of lift or more should be paired with an aftermarket upper arm regardless of the lift height they are set to, to avoid ball joint bind or contact with the coil and stock arm.

When do I need a differential drop?

Generally, we recommend a differential drop on spacer style lifts over 2.5” or with any coilover capable of achieving over 3” of total lift.

How do I know what UCAs to run? (Small Taper vs Large Taper Ball Joint) How do I figure out what upper control arms my Silverado/Sierra have and which ones to buy?

From 2007 to 2018 GM used three different kinds of upper control arms with two separate ball joint sizes. Vehicles with Aluminum (silver) or stamped steel (black sheet metal) upper control arms use aftermarket upper control arms with large taper ball joints. Vehicles with black forged steel upper control arms use aftermarket upper control arms with small taper ball joints.

Upper Control Arm Material Types, Stamped Steel, Aluminum, Forged Steel

What size tires can I run with most 2-3” leveling kits?

In most cases, you can run up to a 33x11.5 or equivalent size in tandem with an aftermarket wheel with a 0 offset or lower with minimal to no trimming. Backspace will vary on rim width.

Do I need the shocks with the reservoirs?

This is dependent on how you are using the vehicle. If during any of the driving you are doing you see a marked degradation in ride quality over the duration of the trip, trail run, or off-road trek it may be a good idea to upgrade to a shock with an external reservoir.

What kind of shock do I need to reduce all the body roll and bounciness from towing?

We typically recommend a monotube shock to properly dampen heavier loads, whether thats in the bed or hitched up like a toy hauler or trailer. Shocks like Bilstein 4600s, 5100s, Rancho RS7MTs, KYB Monomax, are all significantly better than stock shocks in handling loads.

What is a good budget beginner off-road shock?

On a budget, the Bilstein 6112’s (Front) and 5160’s (Rear) are very hard to beat. On the front, you get a 2.6” shock similar in size to the Fox, King and Icon 2.5 series coilovers and the rear you get a 46mm (2”) piston shock with reservoirs. All for a similar cost of a set of coilovers from the other brands.

What are the best off-road shocks available for the Silverado & Sierra?

This depends on the kind of off-road driving you will be doing. If you want the best off-road performance and like being out in the desert, the linear valve of the Fox and King suspension is what you would want to go with. King has 3” series suspension for the Silverado which use a 3” piston in the front and rear, with the rear being external bypass shocks. This will give you the best performance off-road without going with a long travel setup. If you are getting together an overlanding type of build, where you need the suspension to perform as good on-road as it does off-road with the heavier builds, the digressive valving in the Icons is the way to go. Fox, King and Icon all have adjustable damping options that are also worth taking a look in to.

What kind of shocks do I need for my 4” / 5” / 6” lift kit?

For most lift kits on the market, for the 2007+ GM 1500 platform, the lift systems typically use strut spacers on top of the factory front struts to achieve the 4”, 5”, or 6” of total lift. For the rear, typically a lift block or add-a-leaf pack is used to achieve 4” or 5” of lift; a height that keeps the vehicle level front to rear so this sometimes varies.

So for these lift systems, most people replace the front struts with factory height struts, and then replace the rear shocks with extended length shocks.

Most shock manufacturers do not produce extended-length struts, and if they do, they’re just creating an extended mount on a factory-like strut. So even though there is a 6” lift kit, that doesn’t actually mean there’s 6” more of travel from the front suspension/struts; the lift was achieved by relocating various suspension components down, relative to the chassis of the vehicle.

If I buy new struts, do I need new springs?

Aftermarket struts will use the factory springs.

Most coil springs can easily last 200,000 miles on a daily driven vehicle. If the Silverado has been used heavily as a work vehicle, then the life of the springs will degrade more rapidly, and its advised to change them out once the vehicle hits 200,000 miles, or sooner, depending on overall suspension health.