scedule 40 pipe IS pretty strong!!..
I agree that schedule 40 pipe is some hefty stuff!...they also make
schedule 80 pipe!!..I bet that buggys"cage" is as strong as a stock pickup cab at the very least,despite its lack of triangulation...I'd be more worried about getting tossed out of it,and having it land on top of you, than getting hurt in a roll-over in it...
You guys would cringe at the "ice races" we have here in New England,if that buggy scares you!..the "cages" they use in them are often just pipe,not even schedule 40!--and they get T-boned at 70+ mph,and its rare for anyone to get injured...they roll over once in a while too..most of them just get flopped back over and go back to racing after a crash...
We actually built a go-cart from electrical conduit at the junkyard one winter when we were bored,and had a junked step-van come in full of electrical condiut and other electricians goodies!..and we BRAZED it together with the oxyaxcetalyne torches! (all we had at the time!)...
I was very suprised how strong it was--my co-worker was mostly the one who "engineered" it--it was a clone of a Honda Oddesy,it was more like a sand rail than a go-cart..it was only 1/2" and 3/4" conduit,but he used lots of triangles and gussets where it counted..I found a 8 hp Airens sno-blower in another junked pickup trucks bed,and I got it to run again--soon we were having "races" in the huge quonset garage!--we hit some immoveable objects pretty hard with it,and I was impressed at how little damage it got considering the impacts..we rolled it over at least a dozen times outside!!

--I appreciated the full cage then!...to my suprise,the conduit wasn't quite as weak as I though it'd be...I wouldnt use it for a roll bar or cage on a 4x4 though...

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