I’ve refined my safety cage a bit and done some more research into safety cages used in racing. I found a kit that featured 1.75″ tubing with .135″ thick walls. Running that through the online weight calculator I’d found, that comes out to 2.133 lb/ft. I also did a calculation on 3/4″ tubing of the same wall thickness for use in cross ties and such. Figuring out the length of the tubing in this design, I was able to do some weight calculations:
This is all obviously napkin math, but the result is pretty surprising. If I use the 1-3/4″ tubing for the main structural hoops, then tie it all together with 3/4″ tubing, my entire safety cage and main chassis would only weigh about
100 lbs 130 lbs. This doesn’t include some sub-frame pieces and none of the front suspension components, but still, that puts me well on my way, I think, toward making my < 600 lb design criteria.