Hi Les,
The shock is unknown brand, I bought a junked bike and stripped it off of that. My vendor has my intended spring/shock on back order. So when I get the right one, I have to rebuild the swing arm and shock mount bit to fit that shock. This is a prototype, so there have been a lot opportunities for change. Pretty ugly at this point, isn't it? Most of the welds are actually tack welds just for that reason.
I don't know what a drop out is, but yes, the swing arm is not a triangle. It is two pieces of .08? oval steel tube with 3/16" plate for actual mounting the wheel. Is that the drop out? Yeah, I know about triangles being strong, but one of my professors taught me that if your only tool is a hammer, you tend to see every problem as a nail. Most of the load bearing structure of the chassis is made from triangular steel tube-like structures. (Made from .029 sheet steel.)
I have no idea what the wide pie wheel and tire weighs, but it is surely more than a normal bike wheel.....And I have no idea what a "MTB" is. I'm not a bike guy, I'm a hot rodder building toys for my grandkids.
I hope to kluge power and control to the hub in the next few days, just to see the damn thing spin.
TTFN,
Dennis