It all starts here with an empty chassis or an in the case of a cargo van, an empty box, or it is sometimes in the industry called an empty can. Truck bodies of every conceivable type get mounted on these chassis. In addition, the commercial truck chassis comes in a wide variety of sizes, lengths and capacities.
The empty chassis is called a chassis-cab, a cab-chassis, and empty chassis. They all work. This truck is devoid of a body on the back and is empty from the rear of the cab rearward. On 1-ton and greater capacity chassis, the frame width has been standardized throughout the industry often to 34″. This truck was never designed from the factory as a completed vehicle. This makes it easier for body companies to build bodies for various chassis manufacturers. On lighter duty trucks, the frame rails are not standardized in this way because these trucks were designed for a pickup box and is available as a pickup box delete option to deliver the chassis to the dealer or a body company minus the pickup bed.
The chassis cab is available in a conventional cab style (a front end just like a pickup), a cutaway cab style (a front end that is just like a cargo van), a tilt-cab for cab over applications and a stripped chassis for step van and RV applications.
The most popular is the conventional cab chassis and on most models it is available in a regular cab, extended or double cab and crew cab body style. This is available in light duty box delete (1500 & 2500HD), regular cab chassis (3500HD), and medium duty cab chassis (coming in 2018).
The cutaway chassis is very popular for van bodies mainly, although other types of bodies can be used. An example of this is the Knapheide KSV body. The main advantages of the cutaway style chassis are lower entry height, shorter turning radius, and inexpensive maintenance. These are available in 1-ton (3500) and HD 1-ton models (4500). They are also available in several different wheelbases to accommodate body lengths up to 16′. The cutaway chassis is also popular for RV use in motor homes and campers.
The tilt-cab style chassis, or low cab forward is available in 3500 & 4500, as well as 3500HD, 4500HD, 5500HD, & 5500XD models to handle bodies from as little as 10′ up to 20′.
The stripped chassis is a chassis without any kind of cab at all and it is used for step vans (like UPS or Bread Trucks), for HD use (like tool companies), and for RV use for class A motor homes. GM does not make this chassis at this time, but has in the past.