Tube size for custom frame

[Home_brewd]

I started building this 4 door Willy’s pickup a few months back and had thought I was going to use the factory Willys pickup frame and just box it in and add some crossmembers to handle a 6.0 LS, 1 tons and 42-44s for some western rock crawling. But after finally getting the body put together enough to drop it on the frame I started thinking it might be easier, lighter and stronger to build my own frame. The factory frame is 2x5 1/8” C channel.
So my question is, what material should I use? Is 2x4 .120 strong enough? Or should I go with .188 wall or even 2x5 .120 wall. Any other suggestions? What’s your experience?

 

[BUCKWILD]

what kind of wheelbase you going for? 2x4x.120 is good but 2x4x.188 will be better if you are looking at good power and tires for out here, just my 2 cents

 

[Tech Tim]

what kind of wheelbase you going for? 2x4x.120 is good but 2x4x.188 will be better if you are looking at good power and tires for out here, just my 2 cents

^^^^ What that guy says.

Depending on Wheelbase and intended use, the 2x5 .120 wall might even be better.

Do you have a build thread going yet? Would love to see what you got going.

 

[Home_brewd]

I appreciate the input.
I’m shooting for under 140” wheelbase. I haven’t started a build thread yet but I might once I get into building the suspension.

what kind of wheelbase you going for? 2x4x.120 is good but 2x4x.188 will be better if you are looking at good power and tires for out here, just my 2 cents

^^^^ What that guy says.

Depending on Wheelbase and intended use, the 2x5 .120 wall might even be better.

Do you have a build thread going yet? Would love to see what you got going.

 

[arse_sidewards]

I vote 5x2x.120

If this were a working truck and not a toy I'd say you have a half ton truck's wheelbase so copy a boxed half ton truck frame.

 

[JohnnyJ]

I'd go 2x5x0.120 and laminate any area I thought I was worried about.

 

[the_white_shadow]

2x3x.120 will be just fine. My last crawler had the same drivetrain and 43s and it never skipped a beat. Your'e going to tie the cage into it and add crossmembers to stiffen it up. No reason to add unnecessary weight.

 

[arse_sidewards]

OP didn't say anything about a a cage.


You can get away with a wet fart of a frame if you have a cage. No cage and you're gonna bend shit quick if you go undersized.

 

[the_white_shadow]

OP didn't say anything about a a cage.


You can get away with a wet fart of a frame if you have a cage. No cage and you're gonna bend shit quick if you go undersized.

Pretty dumb for the OP to not have a cage.

 

[Home_brewd]

2x3x.120 will be just fine. My last crawler had the same drivetrain and 43s and it never skipped a beat. Your'e going to tie the cage into it and add crossmembers to stiffen it up. No reason to add unnecessary weight.

OP didn't say anything about a a cage.


You can get away with a wet fart of a frame if you have a cage. No cage and you're gonna bend shit quick if you go undersized.

That would have been helpful information to add I guess. Yes, 1.75x .120 cage and 2x6 .188 boat side rockers.

 

[mobil1syn]

if you are caging it, i would do 2x4x.120 and peel out

 

[2big bronco]

2x4x120 and plate any crucial areas or cage tie ins.

Unless 2x5 just makes it easier to do 1 large flatbelly skidplate

 

[Sterlingfire]

Best of both worlds, 2x5x.120 under the cab and 2x3x.120 for the cargo area and the same for the engine bay. Just make nice tie ins to the 2x5 with the 2x3 cut and notched on top of itself. Unless you don't need the sub frame height under the cab then go 2x3.

 

[FordFascist]

I’ve been rocking my custom built 2x4x120 frame for 15 years now with zero issues.

One of the smaller strength adders that many forget to do is the bulkhead the tubing at joints and bends. It keeps the joint from deforming under a bending load. Most fishplate but I would recommend those bulk heads as well as fishplates.

If you are looking for more weight carrying strength, go with a larger height of tubing. Wall thickness helps against denting and gouges but is not that effective against beaming and torsional strength compared to an increase in tubing height or width.

 

[Penetrode Offroad]

Echoing what Sterlingfire is saying about tube size. 2x5" from foot well to back of cab to make packaging and flat bellying easier.

 

[NDCjeepsmith]

One of the smaller strength adders that many forget to do is the bulkhead the tubing at joints and bends. It keeps the joint from deforming under a bending load. Most fishplate but I would recommend those bulk heads as well as fishplates.

What exactly do you mean by "bulkhead"?

Like cap the main rail before moving on to the next section. Like an internal gusset?

 

[FordFascist]

What exactly do you mean by "bulkhead"?

Like cap the main rail before moving on to the next section. Like an internal gusset?

Yes. There are some examples in my build thread if you want to check it out.