Originally Posted by
sjofels
well after a few ( careful) testrides it still holds, most old fashioned folding and recumben tbikes have one tube by the way. so, gonna try (and maybe fail, but there is no shame in failure) it anyway.
sjofels; Noting your example of bikes with single main tube are bikes that have that tube used in a completely opposite part of the frame design. If you were to remove the top tube from your design and replace it with a down tube, then your revised design would be closer to the examples you cite and would be at least marginally viable. Of course putting in both tubes will dramatically improve the strength...
/K