Those are RSG sliders...
Will you please elaborate on the pinch weld idea more please?
I hate to derail this thread.
The basic idea is pretty straight forward. Rock sliders are cantilevered beams that attach with mounting plates to the frame. The frame rails are something on the order of 12ga high strength steel. They are not strictly rigid - ie. they will flex. No matter how strong your slider is - the frame you're attaching it to will flex when you drop the weight of the vehicle on a rock on the slider. When it flexes it should contact the pinch weld on the bottom of the body. That's where the force is transferred to the body on hard impacts.
Lifting in slow controlled lift with a floor jack is not the same thing as dropping a foot off a rock onto the slider. So demonstrating lifting with a jack is pretty pointless unless unless that's all you intend for the slider to do. If so - that's a perfect test. It applies about 2500lbs of force. In comparison an 18 inch drop (I think near the extreme of what reasonable design would withstand) - is going to apply about 4900 joules. How much it deflects dictates how much instant force. If it were nearly rigid and only deflected 1mm, it would impact with 110,000lb of force over that 1mm. If it deflects 5mm or 1/4 inch, that's only about 22,000lbs of force, and if it deflects 1cm, it's about 11,000lbs of force. The point of those figures is to show that it doesn't make sense to try to resist deflection. It's much better to accept it and build to transfer it to the body structure.
So the frame is going to flex and the slider is going to flex into the body mount. And you want it to to that. It's much better than having all the load transferring a twisting moment to the frame rail. So it's both better AND lighter. The solution relies on the body as part of the system though. Doing that means that you need to spread the load of the impact over the pinch weld as much as you can. That's why most sliders use a square tube under the pinch weld instead of a round one. And why they place the square tube directly under the pinch weld. It's not only an easy design, it's also a very good design from an engineering perspective. The other result of doing so is that you can have much lighter material in the beams that attach and frame mounts.
Not mounting the square tube under the pinch weld means that the beams that attach the slider to the frame rail are then going to contact the pinch weld. They are spreading the load on a much smaller portion of the pinch weld and, depending on how hard you use them, will eventually bend the pinch weld.
Hope that helps explain it.
If the plan is to use as heavy duty running boards that occasionally bump into a tree or rock - they're probably all equally good. If the idea is to withstand repeated drops - you want one with a design that's intended for that type of use. The aluminum ones would not hold up to my abuse over time. But that doesn't make them bad. They offer a significant weight reduction and for many people they're perfect. And they'll probably do great for occasionally use and resist the hard impacts once in a while.
op2:
