Me and a friend were having a friendly debate on truck frames the other night. He's a brainwashed Ford guy, and I'm not exactly %100 up to snuff on truck frames.

My friend thinks that the new Ford frames are the best out there, because Toby Keith said so.

Ford is fully boxed, but isn't Dodge Fully Hydroformed? Then there's the gmt800 that's hydroformed up front, what's the rest?

oh, and then there's the Ridgeline with a boxed frame front and back and unibody in the center? is that right?

Discuss...

How do they all stack up?

 

Right now in terms of total strenght I would put my money on the Ford. But with GMT900 around the corner things could change really quickly.

Also lets not forget that boxed frames are not always the absolue best, semi's use c shaped frames.

 

That's only for the flexibility though, right? Pulling huge loads you'd need it or you'd think things would start cracking and busting. Is this the reason the GMT800 is c-channel in the rear?

 

I don't know if that is the reason but if the steel stretches in the open part of a C channel it doesn't mean it will break. Steel has a high tensile strength and that means that its stretching would be linear and easliy predicted, though the same holds true for a boxed frame.

 

It's all marketing. Everytime some manufacturer comes out with a fully redesigned truck platform we hear how the frame is x% stiffer/stronger than the one it replaced. If you go back far enough, what, does that mean trucks were built out of uncooked spaghetti back in 1970?

It's all in how you spin the numbers. So while the F150 might be "stiffer" in one way the GMT800 might be in another way, depending on how you want to test each frame.

 

The Ford SuperDuty frames were updated for the 2005MY. From the gist of it they took the F-450/550 frames and now use those on the F-250 and up. These frames are thicker than the frames they replace. How this stacks up to the competition?

Boxed is describing construction, ie no open channels. Hydroforming is a process in which the steel frame is shaped with high pressure water.

GM was the first to use this Hydroforming process on the GMT800 truck frames.

The truck from on my 2002MY GMT800 2500HD is Hydroformed and fully boxed until about he mid point of the front passenger doors. Then it transforms into a C channel the remainder of the way back.

Here's mine loaded down, notice no bending or twisting of the truck.


Some members of our family do a little firewood business in the winter. My brother regularly loads his 2002 2500HD towing a goose neck trailer loaded up to the GCWR limit of 22,500 lbs and not a pound more Yet to have any frame issues at 100k miles.

The basic point is the frames put under the Big3 trucks are all good. The measurable differences between frames isn't humanly discernable. Least most of our SOTP meters couldn't tell the difference.

What does your buddy's frame in the Ford allow him to do that the owner of a Dodge or GM couldn't?

If your looking to give your buddy a nice shot back you could just bring up the 6.0 liter PSD that's been stellar.

 

All steels don't have the same ultimate strength, but they have the same modulus of elasticity. I think that you may be getting that confused.

The ultimate strength of a material is the point in which the material breaks. Do the composition of the steel as well as other factors, it's ultimate strength can vary greatly, bur it's modulus of elasticity is always the same.

The modulus of elasticity is the slope of the linear portion of a stress-strain curve. It is what determines the ductility of a material. The lower the modulus of elasticity the more elastic the material. It's also the proportionality constant in Hooke's Law. This is what allows the stretching to be easily predicted.

The only difference between a C channel and a boxed frame is it's moment of inertia. A design with a high moment of inertia will resist bending, torsion and other stresses.

Anybody saw the infomercial for the little giant ladder system. The one with the dude that played Al Borland in Home Improvement and that ladie from Hometime. Well the little giant ladder has boxed sections. They compared it to a regular open section ladder (I-beam cross section). In one of the demonstrations they applied a torque to a leg of both ladders. The open "regular" ladder exhibited a lot more twist than the boxed little giant. They were able to twist the leg of regular ladder a couple of turns. They couldn't twist the little giant more than a couple of degrees.This is due to the little giant having a larger moment of inertia. Both ladders were made of Aluminum, same modulus of elasticity. The same basic principle holds for truck frames as well.

As for which design is better, who knows? Numerous variables come into play.
Just wanted to clear a few misconceptions.

 

Chrysler's up there, but I'd have to give the nod to Ford as well.

Don't know a thing about Ridgelines. Sorry.