>>1347585>I-beamNo, it´s a rectangular profile.
I-beams have very low torsional strength, but can take high loads in other directions.
Tubes have high torsional strenght, but are weaker in other directions.
Rectangular profiles are a compromise between both.
Anyway, that seems to be a pretty efficient frame design and it looks like it is possible to include a suspension in there as well without adding much complexity.
