A lot of people want to run some larger tires on their LM2 trucks for off-road capabilities or just to improve the look of their truck. The stock "Rancho" shocks leave a lot to be desired when it comes to performance, they are floaty and we have seen them fail very prematurely. One cost effective way to solve this issue will be to upgrade the front struts and rear shocks with a set of Bilstein 5100 series shocks, these were designed specifically for the GM 1500 platform and are valved to improve body control and eliminate that "floaty" feeling that the stock trucks have.

The Bilstein shocks utilize the factory springs so you won't experience a harsh ride from an increase spring rate, they also have multiple ride height settings that can be adjusted with the snap ring on the shock body. This allows you to lift the front of the truck up to 3" over the factory setting on most trim levels.1

Click image for larger version

Name:	lm2 front shock.jpg
Views:	1
Size:	80.2 KB
ID:	5983

When lifting the front end or adding larger wheels and tires to these trucks it is vital to upgrade the upper control arms as well. The factory suspension is lacking and has a tendency for the upper control arms to fail and have the ball joint pull out of the socket.
Click image for larger version

Name:	broken uca.jpg
Views:	1
Size:	95.8 KB
ID:	5984
By upgrading to an aftermarket control arm, there is more droop travel and they offer heavier duty ball joints, the Dirt King upper control arms utilize a MOOG Problem Solver ball joint that has a much larger design than the OEM control arms.
Click image for larger version

Name:	lm2 front shock-1.jpg
Views:	1
Size:	94.0 KB
ID:	5985

By utilizing this combination of Dirt King upper control arms and a set of Bilstein Struts, the suspension is much more robust than it was when it left the factory. The ride quality on these kits is much improved over the stock ride and gives the driver much more control over the vehicle and it handles large potholes and bumps much better that the rancho suspension was ever able to do.

We took our 2021 Chevrolet Silverado 1500 RST LM2 over to the guys at Duramax Service Center to go ahead and throw these parts on our truck to level it out and allow for larger tires in the future.

Click image for larger version

Name:	luis lvl kit-4.jpg
Views:	1
Size:	140.7 KB
ID:	5987 Click image for larger version

Name:	luis lvl kit-1.jpg
Views:	1
Size:	179.0 KB
ID:	5988
After a week of driving this truck around town we have been very impressed with the quality of these parts. The factory Rancho struts were almost useless after only 20,000 miles, with close to zero compression on the struts they really weren't doing anything to stabilize the truck or help with ride quality. You would drive over a speed bump and it would take 4-5 bounces before the truck stopped, with the Bilstein shocks it was a huge improvement and would immediately stop bouncing after going over speed bumps or any road undulations.

We decided to put the front struts on the 4th setting to provide 2.75" of front lift bringing the front fender height up to 40" and it really changes the entire look of this truck. The front height is now at 40" and the rear is 39.25".

If you are using your GM 1500 truck to tow or you do load down the bed regularly, we recommend to increase the rear ride height or install some sort of load support such as a set of AirLift airbags, RAS, or Timbren load support stops. This will help keep the truck level when loaded down and will increase the support and make towing a much more composed experience with less sway and bounce.
1AT4 and Trail Boss trucks come from the factory with a 2" lift in the front and rear.
Attached Files