2021 GMC Sierra 2500 AT4 Build

2021 GMC Sierra 2500 AT4

Build List

     – 20″x10″ Fuel Off-Road Reaction Wheels

     – 35″x13.5″x20″ Nitto Recon Grappler Tires

     – 3.5″ Front & 2″ Rear ReadyLIFT SST Lift Kit

     – Painted to Match Bushwacker Fender Flares

     – Gorilla Lug Nuts, TPMS Sensors, Alignment


2021 GMC Sierra 2500 AT4


2021 GMC Sierra 2500 AT4

What The Customer Was Looking For

20"x10" Fuel Off-Road Reaction (-18mm)

The customer came to us knowing what wheel he already wanted and in what size, which was the Fuel Reaction finished in a gloss black milled with red tint. 

The size he was looking for was the 20×10, which came with a -18mm offset. The combination of the wider wheel and negative offset would push the wheels and tires out past the fender of the truck helping to give it more of a stout stance.

The Reaction comes in three different finishes but this one with the red tint matched well with the red accents that were already on the truck including the GMC emblem, the tow hooks, and the AT4 emblem. 

Fuel Off-Road Reaction

35"x13.5"x20" Nitto Recon Grapplers

Next up were tires. The customer was looking to get 35’s, and he also wanted something that would ride nice on the road but still have a somewhat aggressive tread pattern.

We decided to go with the Nitto Recon Grapplers, a new all-terrain tire from Nitto that is designed to perform well both on and off-road. The tire is also long lasting, which is reflected in Nitto’s 55,000 mile treadware warranty.

We were deciding between a width of 12.5″ and 13.5″, but we ultimately went with the 13.5″ as it would help to achieve the look we were going for, and it would help to better accommodate the 10″ wide wheels.

Nitto Recon Grappler & Fuel Offroad Reaction

ReadyLIFT SST Lift Kit (3.5" Front & 2" Rear Lift)

Next, we had to do some research for a lift kit that would make it possible to fit 35’s as well as one that was not too big as the customer wanted just a slight lift. 

We went with a ReadyLIFT SST kit that we had actually put on another 2021 GMC Sierra 2500 before, which gave the perfect amount of lift. It was big enough to fit 35’s but not so big that it would be overbearing.

What is great about this kit is that it provides 3.5″ of lift in the front with 2″ of lift in the back, which not only lifts the truck, but it also levels it out.

The kit comes with beefier upper control arms, Bilstein shocks, newly indexed torsion keys, beefier tie rods, and various other components to correct the suspension geometry.

ReadyLIFT SST GMC 2500

Painted to Match Bushwacker Fender Flares

Another part that was introduced later into the build was a set of Bushwacker fender flares. As previously stated, the width and offset of the wheels would push the wheels and tires out past the body of the truck. With the strict laws we have here in Massachusetts this would pose a problem when it would come time to get an inspection as you are not allowed to have your wheels and tires poke out past your fender. This would mean the customer would have to put on his stock set of wheels and tires when going to get an inspection.

Another way to solve this problem would be to install a set of fender flares, which would legally extend his fender out covering his wheels and tires putting him in accordance with state law. Along with this we also thought the fender flares would help to add to the aesthetic of this truck. 

Since we are a body shop at heart we thought it would be a good idea to paint these flares to match the color of the truck. We professionally matched the paint through our Glasurit paint mixing system to achieve the same color that was on the truck. From there we prepped the fender flares for painting and put them into our AFC downdraft bake spray booth to get a factory quality paint job. Once done we let the paint bake on the flares to get a quality finish, and then we fitted and installed them on the truck. The end result was a pristine set of color matched fender flares that looked like they came with the truck from the factory.

Painted to Match Bushwacker Fender Flares
2021 GMC Sierra 2500 Bushwacker Paint to Match Fender Flares
Fuel Off-Road
Bushwacker Logo
ReadyLift Logo

Before & After

2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4
2021 GMC Sierra 2500 AT4