OBS Chevy/GMC C1500

OBS Chevy/GMC C1500 Lowering

Old body style (OBS), or more specifically 88-98 Chevy and GMC full size trucks are becoming incredibly popular to customize. When these trucks were new, we lifted or lowered hundreds of them. There were 4 basic static drops. Static means without air ride.

  1. 2” rear drop using lowering shackles.  This leveled the truck out instead of sitting nose down.
  2. 2” front, 4” rear drop using either springs or preferably spindles in the front and shackles with hangers in the rear.  The rear is basically moving both leaf spring mounting points up.
  3. 4” front, 6” rear using spindles and springs in the front and a “flip kit” in the rear.  The flip kit relocates the rear axel from the bottom of the springs to the top of the springs.  When you do this, you have to notch the frame or else the axle will bang against the frame and it’s obnoxious to drive.
  4. 5” front, 7” rear using spindles and springs in the front and a flip kit combined with shackles in the rear.  This one is basically taking the 4/6 drop and cheating a little so you can really get it sitting right.  You will sacrifice a little ride quality, but it looks great.

The other way to go is air ride suspension. You still use the drop spindles in front but replace the coil springs with air bags and move the shock to the outside of the control arms. The leaf springs are eliminated in the rear and replaced with a four link combined with a track bar or watts link to keep the rear end centered side to side. Air bags are mounted between the axle and frame to control up and down movement.

One misconception about air bags is by installing them you can get your truck to lay on the ground. Although it will go pretty low when “aired out”, it takes a lot more work if you want that look where the rocker underneath the door gets close to the ground. There are many things stopping it from doing that. The front tires will hit the inner fenders. To correct this, you must relocate all that is connected to the inner fenders and fabricate new ones. The rear end will hit the bed floor. To correct this, you must raise the bed floor. As you can see, a lot of fabrication goes into the trucks that will sit low enough to lay the rocker on the ground.

There are companies that manufacture aftermarket frame assemblies that look great and will get your truck on the ground. GSI Machine and Fabrication builds a really nice frame designed to get this body style on the ground. Roadster Shop recently introduced a frame for these trucks that will set the truck low without raising the bed floor. They use a late model independent rear end to gain the necessary clearance to accomplish this.

We can help you either way depending on which look you are after.