TomG2 wrote:
I had not heard (or read) that was the way it works. References please.
As I stated in my post on page 2, some trucks are limited by the class they are in rather than the capabilities of the truck.
Take my 2014 Ram 2500 for example. It is in class 2B which has a minimum GVWR of 8,501 lbs and a maximum if 10,000 lbs GVWR. My truck is limited by the class it is in rather than the sum of its parts. How can I say this? Easy, take a look at the parts and their ratings in other vehicles.
My 10,000 lbs GVWR Ram 2500 with a little over 2,100 payload shares the same engine, transmission, front axle, front suspension, rear axle, tires, axle gearing, driveline, brakes, and frame as the SRW 3500 CTD 11,700 lbs GVWR that has a payload of over 3,900 lbs. How is it that my truck has the same front GAWR of 6,000 lbs as the 3500 and a rear GAWR of 6,500 lbs, which is only 500 lbs of the 7,000 lb rear GAWR of the 3500, yet my truck has almost 2,000 lbs less payload. Remember, they are identical trucks except for the rear suspension which is only rated to handle 500 lbs less by their GAWR. If you take away 500 lbs from the 3500s 11,700 lb GVWR, then that would leave you with a 11,200 lbs GVWR which would give me a payload of well over 3,000 lbs.
Lets see what that rear suspension can handle in other trucks. In the identical truck like mine, but with an almost 1,000 lbs lighter 6.4L, the truck has a 10,000 lbs GVWR with over 3,100 payload. Hmmm, seems odd. I have the same rear coils as this 6.4L in my CTD, yet it is only rated the exact weight difference of the engine. Now, before you say "the extra weight of the engine is what does it". I would like to remind you that the rest of the truck is the same as the 3500 which is rated to handle much more weight and the engine rests on the front axle system which should not affect the rear suspension at all. Besides, my truck has a 500 lbs more front GAWR than a 6.4L does.
So why does it have less payload even though the very same coils in the rear can handle more in another truck? Because my truck reaches the max GVWR of it's class long before it reaches the capabilities of its parts. If my truck had the same payload as the 6.4L version of mine, then it would give a GVWR of over 10,000 lbs which is a class 3 truck and is where the 3500 truck resides. Ram has to comply by this class rating and so does every other manufacturer. Most trucks in class 2A(which is where most "half tons" reside) are far from hitting the max of their GVWR for their class, but most trucks in the class 1 and class 2B classes are maxed out by the max GVWR of their class.
EDIT: it looks like you changed your wording to add " for pickups like the OP's F-150" after I posted my response.