What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Frame boxing

Something Ive been considering is adding, round tube crossmembers similar to the GMT800, and probably newer trucks have. Obviously would have to be towards the rear of the frame for clearance from drivetrain components.

Would frame boxing, say from in front of the cab, to a couple feet past the cab be of any benifit?
 
I was thinking that too. Im not an engineer, just a dude wanting to restore a truck to tow some with. Im probably overthinking things, but more frame strength is never bad.
 
Bent77 said:
Would stiffen the frame some

Might also create some new stress points where the boxes sections end?
Click to expand...
Yep, either do it all or do nothing. It’ll just twist where it can probably even more in the parts that aren’t boxed since all the twisting will take place in the weak spots instead of being evenly distributed along the entire frame rail.
 
Good point.

Would there be a difference between my intended use, mainly on road, 3" lift max with 285's, and a truck that gets wheeled hard?
 
The factory doesn't worry about boxing the whole frame.
Here is my company truck. An '07 GMC K2500 gasser.
The front is boxed, but then they do some playing around....
The first pic is just ahead of the torsion bar crossmember, then behind it. Then rear shock.
Note how there is a section in the 1st pic that has no lip on the flange, makes it a standard flange, right where the box ends.

20171102_115530.jpg

20171102_115524.jpg

20171102_115515.jpg
 
I wouldn't compare square body frames to any newer truck, the entire process and likely the materials used in building "modern" frames is completely different.
 
But what kind of steel is available for fabrication? Would it be similar to the existing material in the frame of the square trucks?
I understand that the material is different from new to old, but I wouldn't think that the design can't cross at all. Some adaptation should be acceptable. IMO...
 
I'm not sure it's materials as much as it's the engineering and technology that is available for both the design and manufacturing process.
 
I was mostly referring to the process more than materials, hydroforming is supposed to greatly strengthen the frame.
 
What about fish plating the outside of a frame like what they do on the big truck stuff? Won't stiffen it a ton but adds strength. Also welding all of the riveted on crossmembers helps stiffen a ton. A guy I used to work with did demo derby stuff and he would pull the body off his cars and weld all of the seams on a factory boxed style car frame where the factory would only stitch them every so often and it was amazing how much stiffer they would be.
 
I would think that partial boxing would move the load the frame is taking hit the end of the boxed section that much harder.

On @6872xtc first pic, you can see the factory put an extra plate on the bottom of the frame probably for just that reason. Also, it kinda almost looks like there's a crack right in front of that plate - or is that just dirt markings...?
 
JoshHefnerX said:
I would think that partial boxing would move the load the frame is taking hit the end of the boxed section that much harder.

On @6872xtc first pic, you can see the factory put an extra plate on the bottom of the frame probably for just that reason. Also, it kinda almost looks like there's a crack right in front of that plate - or is that just dirt markings...?
Click to expand...
I will have to check it out in the morning!!
I don't spend too much time under this truck!! But we check the big trucks all the time!!!
 
I think tying a cage into the frame does much more than frame boxing. My rock sliders are welded to the cab, sliders have supports going to the frame. Exo cage, flatbed, and front engine cage are all welded to the rock sliders and frame. With the suspension all flexed up, none of the body panel gaps look any different and the doors open and close just fine
 
OK, so i'll chime in here if ya don't mind.

Boxing the frame helps each rail resist twisting. Couple that with the appropriate cross members and you have done a lot to eliminate the twist in the entire chassis. Its difficult to make cross members do it all with out some resistance to twisting in the individual members themselves. Sometimes you can't put cross members where you'd really like to. Things are in the way and its not realistic. For instance, hard to put a cross member through the transmission. That's where a roll cage can come into the picture. although, most people are not putting in a cage to stiffen the frame, it will have that effect and again, depending on the design of the cage it can have a profound effect on the frame rigidity. At the same time, a cage can introduce stress risers to the frame that weren't there previously. A boxed frame will help prevent that. All of them can work hand in hand can compliment each other. IF you're in a place where you can box the frame I'd recommend it but to each his own.

One of the best parts of this conversation is boxing sections of the frame. Most people agree that you can do more harm this way and I agree unless it is done correctly. So, if boxing a frame in partiality will cause a frame to crack where the boxed section ends, you start to realize how much twist is in each frame rail. We're using the frames for much more than they were intended. Just food for thought.

Comparing a frame that is intended for off road use to any frame that GM has ever released in a light duty truck is comparing apples to oranges. They never intended on them crossing the crack in Moab. So, while the newer GM frames are partially boxed, I tend to think of them as "less I need to box later." IFS suspensions put a very different load on the frame than a leaf spring suspension does. I'd imagine that's a good portion of the engineering that called for a boxed frame section.

.
 
You must log in or register to reply here.

Latest Posts

Top Bottom