Refering to the '01 F350, crew, 7.3L.
Just shopping for shocks and the question came up, "Is that model "chassis on", or "not-chassis-on"? Also, shopping for rails to put in bed for a 5er and the diresctions says, "NOT CAB-ON-CHASSIS".

What are they refering to?
What do I have?
How do I find out what I have?

Puzzling

 

A chassis-cab truck is one like the F-450's and F-550s you see at the dealer with no box on the back. Just a chassis, and a cab. Chassis, i believe it's a stupid french word for frame, or at least thats what it sounds like to me.

 

A truck built as a chassis cab has a different frame than a pickup. A pickup bed won't fit on a chassis cab frame, and neither will 5th wheel rails.

 

ay brothers, I get what a chassis cab is now, thanks, I am guessing now that anything with exc. chassis cab, means excluding chassis cab. yay or nay, anyways yall take care.

 

Or "Except Chassis Cab". Equally appropriate is "excluding". As an example, some rear receiver hitches will fit all 99-16 Super Duty applications except Chassis Cabs."

The reason why some frame mounted accessories like towing equipment that fits pick up frames but does not fit Chassis Cab frames is due in part to the difference in width between the frame rails. Pickup frames are more or less 37" apart at the vertical web, while Chassis Cabs conform to the common NTEA standard of 34" width between the vertical webs of the frame rails. The 34" spacing is common to most brands of commercial truck chassis frames, from Peterbilt to KW to Hino to Isuzu to International to Freightliner to the F-650/750 and the F-450/550.

Ford makes two versions of F-350 without a pickup bed. The first version is called a "box delete", and while it may look like a chassis cab because it doesn't have a bed, it actually has the same frame as the pickup, otherwise referred to as a "wide frame". And this is where it could get confusing, because Ford also makes an F-350 without a pickup bed in a "narrow frame" version, and this would be considered a true "chassis cab", with a frame designed to accept universal vocational bodies that could be equally fitted to a variety of truck brands.

The universal fit is possible due to the National Truck Equipment Association's efforts many years ago to encourage chassis manufacturers to abide by certain common measurements to enable vocational body manufacturers to build one type of service body, dump body, flat bed, fire apparatus body, etc that could be mounted to a variety of truck brands with relatively equal ease of fitment.

Pickup frames typically have an arching hump over the rear axle, which helps increase the range of suspension travel between empty and loaded, as there is expected to be a greater day to day variability in owner operation between empty and loaded states, and, pickup buyers place a higher value on ride comfort in either state.

Chassis cab frames typically have flat straight frame rails, for ease of vocational body equipment mounting. But there are more differences than just the shape and width of the frame rails. There is also a commonized cab to axle distance in Chassis Cabs that differs from pickups. For example, the F-350 "box delete" option that only looks like a chassis cab, but isn't... uses a wide frame that will have a 56" cab to axle distance. By contrast, the true and genuine F-350 "Chassis Cab" will have a 60" cab to axle distance (or an 84" CA, depending on the number of doors in the cab).

All of this matters when it comes to buying shock absorbers, which was your original quest and reason for the question. The F-350 pickup, and the F-350 box delete wide frame, both use the same humped frame with only a midship fuel tank and a rear frame mounted spare tire aft of axle. These frames also have staggered shock absorbers in the rear, where the driver's side shock angles rearward, and the passenger side shock angles forward.

By contrast, the rear shock arrangement of the narrow frame chassis cab has BOTH shocks angling forward, as there is an aft axle fuel tank on the narrow frame that isn't available on the wide frame. There are also spring rate differences, drive shaft differences (ie single vs double cardan joints, etc) and suspension travel differences that when considered in combination may warrant a different shock valving. But the most tangible difference that you can actually see is the shock mounting differentiation between pickup frames vs chassis cab frames.

If your F-350 has or had a pickup bed, then it is a wide frame, and therefore anything listed for an F-350, except or excluding chassis cabs, should fit fine for you.

 

Y2K you are an amazing wealth of knowledge. Makes my brain hurt just trying to take in what you share with us here. Thank you for continuing to take the time.

Tried to rep you but I'm in rep jail

 

Rock just bumped a 10 year old thread, but man was it worth it because of Y2's subsequent post!

Stewart