Basis Shock Bench Test (in part by Jack Johnson in Radio Control CAR ACTION June 1995) === PACK >> is the rate at which the shock reacts to any quick, sharp compression. How quickly the oil can pass through the piston. === With the shocks mounted on your car (DUH!!!) so your car is at it's race ride hight and a clear space on your work table. With the front end (tires) on the table, drop the rear of your car from a height of about 6 to 8 inches. The suspension should compress just slightly past the ride height and return to your race ride height. IF the chassis slaps the table, your shocks don't have enough pack. For now change to a heavier shock oil. IF the suspension doesn't move much, you have to much pack. For now change to a lighter shock oil. When your happy with the rear setting do the same testing to the front. When your happy with the front, drop the entire car from 6 to 8 inches, viewing the car from the side the front and rear should compress the same. IF the rear compresses faster than the front change the rear to pistons with smaller holes. IF the front compresses faster than the rear change the front to pistons with smaller holes.