Hybrid cage and cab flex

[A-man930]

How much does the cab flex relative to the chassis?  What are the consequences of bracing the back of the cab?

 

 

I’ll start with the disclaimer that I am not building a proper roll cage – I’m approaching this as a “cab saver” that could probably save my life in a pinch.  This means that there are compromises from structural “ideals” in the name of aesthetics.  

Here are my requirements:

1. Minimal “verticals” to sit outboard of the body.
2. Bed will be in the factory position (I am open to a < 1/2” adjustment rearward by slotting the bolt holes on the chassis side.)
3. Bed will have a tonneau cover; no pass throughs into the bed.  

My solution for the rear is a lower support structure fabricated from .188” wall 2x1 rec tubing.  This will sandwich between the cab and the bed and provide “perches” below the rear glass for the tubular cage.  It will tie into my tube rockers and the top of the frame rails.  

What I can't decide is if I should I weld this structure to the back of the cab, or leave it freestanding.  

I'm prone to weld it, but should I worry about inducing some kind of stress elsewhere?  In a "lean against a a tree" scenario, am I asking to bust the glass out?  At full flex, will the welds to the rockers and the frame be stressed and crack?  

 

 

 

 

[neohic]

If it were me, I’d weld everything together. Especially in a case like yours were there’s so much additional plating and material already, I wouldn’t worry about having too much rigidity. Any seams, I’d cover with a non hardening sealer. 

[A-man930]

1 hour ago, neohic said:

If it were me, I’d weld everything together. Especially in a case like yours were there’s so much additional plating and material already, I wouldn’t worry about having too much rigidity. Any seams, I’d cover with a non hardening sealer. 

 

Good point. There is a lot of reinforcing already:

 

 

 

[jeff351]

I'm thinking that if you weld it to both the frame and the cab, you should be fine. 

I like where you are going with this idea. 

[A-man930]

On 5/2/2025 at 10:50 AM, jeff351 said:

I'm thinking that if you weld it to both the frame and the cab, you should be fine. 

I like where you are going with this idea. 

I'm all but convinced I'm going to weld it.  Thanks. 

[A-man930]

Mocked up the basics.  

[75sv1]

I think I'd put in cross bracing. 

[A-man930]

1 hour ago, 75sv1 said:

I think I'd put in cross bracing. 

Yes. Gravity didn't allow me to mock those up.  

 

[A-man930]

Added a little meat to the top of the frame. 

 

[A-man930]

[A-man930]

[A-man930]

All tacked up. The horizontal piece across the bottom is a temporary brace that'll get cut off after finish welding.