Originally Posted by BlackBoost

Correct! Remember that GVWR is the vehicle weight+payload capacity. Therefore, if 2 trucks are identical but have different engines, then the different weights of the engines will result in different GVWR.

Originally Posted by 8100hd

Manufacturers have to follow many safety standards to set GVWR. Braking, vehicle stability, and manufacturer internal standards for durability, dynamic stability and handling to name a few. This why many vehicles total AWR is much higher than GVWR.

Originally Posted by kbroderick

But the original poster's point was that payload capacity should actually be 100 pounds higher if the engine is 100 pounds lighter, assuming the lighter engine is capable of providing the power needed at GVWR. The chassis, brakes and suspension should all be capable of the same GVWR as the heavier engine, thus switching to a lighter engine should buy you more payload, just as reducing heavy options would.

Originally Posted by doyall

2018? 2.7L may get the LD frame. 3.5 & 5.0 gets the HD frame.

Originally Posted by BlackBoost

I would assume payload is largely calculated with the rear GAWR in mind, whereas the engine puts most weight on the front axle. I can only assume basing on memory, but taking two identical trucks with different engines will have a bigger difference in the fGAWR compared to the rGAWR.

Now the fGAWR should theoretically stay the same, which means an engine weighing 100lbs less means you can load an extra 100 lbs. But weight ratings which take payload into account, are calculated not only by the strength of the frame and suspension components, but also the vehicle's ability to pull, handle, and brake safely. So from a truck frame's perspective, hauling a load above the frame in the bed, or sticking out the back attached to a hitch, is still the same regardless of if the engine up front is 100lbs lighter or not. So that 100lbs being taken away from the front just reduces the GVWR but can still have the same payload.

Hope that makes sense. I tried to find some documentation I've read on it before that's much more specific and clear with no luck, so hopefully what I dug out of the back of my mind makes sense lol

Originally Posted by kehyler

So I found the answer: https://madocumentupload.marketingas...983a7&v5=False

I found two comparison's that I do not understand.

A 145 screw 4x4, the 2.7s and 3.5/5.0s have the same max axle weight ratings yet different max GVWRs?
A 145 screw 4x4 2.7 compared to a 145 screw 2x4 2.7 has a different FAWR and GVWR?

Originally Posted by jp360cj

For the 4x4....No one is going to know for sure (unless they were on the team that made these decisions), but there are 2 likely possibilities...#1, the 2.7EB engine is the limiter for GVWR. In this case, the engine wouldn't "care" if the weight was on the front or rear of the chassis, only that it was present. #2 (I think probably more likely) is it was a marketing decision. With a lighter 2.7EB, the same GVWR as the 5.0/3.5EB would have meant the 2.7 had a higher payload, and Ford can't have that.

For the 4x4 vs 4x2, the 4x4 has more weight, especially over the front axle. Upping the FAWR and GVWR minimize the weight penalty from choosing the 4x4. Whether or not the 4x2 front axle can physically hold the same weight as the 4x2 front axle can only be answered by the Ford engineers.

Originally Posted by kbroderick

The axle itself is, I believe, identical (there's only one axle spec listed in the eSourcebook), but the springs are likely different. As far as the drive axle itself goes, the parts listing only shows drive axles for Raptor- and non-Raptor variations and different ring-and-pinion sets based on gear ratio. It is possible, albeit unlikely, that the 3.73-ratio ring-and-pinion setup is heavier duty than the others.