Okie Terry said:
As I understand it, pipe is much more rigid than DOM tubing. So if you were to end up with the wheels higher than than the roof the pipe would be more apt to break and not provide the same constant protection as DOM which is more flexy and will bend.
Sound about right?
Ductility and Toughness (ability to absorb energy). Pipe is generally much lower in these properties than tube.
When we start talking about SS pipe, I am not sure what the physical properties look like. Given the 1.90" x .100" dimensions you quoted, that sounds alot like 1 1/2" Sch 10S pipe. Right? Sch 10S actually has a .109" wall thickness.
For iron pipe what Okie says is basically correct. While very strong, pipe is not very ductile and thus not very tough when compared to even thinner wall thickness tube. Pipe can fracture under hard impact thus absorbing very little energy. Tube can flex and deform but it is much less likely to completely fail.
Stainless poses an interesting twist to this age old question though.
I can't say definitively that SS pipe would not be a good choice, but my gut says to stick with the mild steel tube.
If you can find some material properties of the SS pipe, start comparing them to those of different tube materials (HREW and DOM) and iron pipe.
Might at least give us something quantitative to evaluate.
