There are various bed lengths, but 2 basic truck bed cargo box designs. Truck beds are referred to as truck beds or as a truck box. The more modern term is a cargo box. The first of two basic designs is the standard bed, often called a fleet side bed or a styleside bed. This is the most popular bed style. The second is the Stepside, often referred to as a flare side, step side or sport side bed.
Standard Bed: A standard bed or standard cargo box is designed with the fender wells on the inside of the bed and they can?t be seen on the outside of the bed. The standard bed is available in a variety of sizes from various vehicle manufacturers. The picture to the left is a Ford F150 with a standard bed that is 6?6" long. Ford calls their standard bed, a Styleside bed, not to be confused with the flareside bed noted above. GMC and Chevy call their standard bed a fleet side bed.
Bed Flareside or Stepside Bed: The fenders are on the outside of the bed. This is how pickup boxes where first made and with the advent of the standard bed, is generally referred to as the "sport model". It is very stylish and is called different names by the vehicle manufacturers. Ford calls it a Flareside Bed, where as GMC & Chevy refer to this bed as a Stepside. Picture to the right is a GMC Sierra Stepside bed.