Are there Open-source bikes?
openbike.org (itself open) has inspired independent projects such as Jetrike (whose author makes plans available).
Expired patents may also count as open source because inventions must be fully disclosed. See for example a linked braking system from 1978, Calderazzo's US Patent #4102439, which makes it very difficult to flip yourself over the bars. (I read about this in Bicycling Science by David Gordon Wilson, Jim Papadopoulos, &amp; Frank Rowland Whitt.)