The world’s lightest folding bicycle that it weighs only 6 kg has been built by a talented engineer Derek Cranage has built his own frame from aircraft spec aluminium, carbon fiber and titanium. Every single item in the bike’s construction is bespoke and trimmed to the last fraction of a gram.
The creation of Derek Cranage incorporates a frame that was designed and built entirely from scratch, with the whole bike folding down into a package measuring 590 x 600 x 260 mm. The three-stage folding process takes just a few seconds, requiring the flicking of three quick-release levers – no wing nuts or other fasteners are involved.
The mainframe of the folding bicycle and the coil-spring-suspended rear triangle are made of a mix of carbon fiber, titanium and 7020 aircraft aluminum tubing, the latter being precisely milled so that it’s thicker and stronger at the joints (with a wall thickness of 2.5 mm) and thinner and lighter in the middle of each tube (1.5-mm wall thickness).
The frame weight after painting and completing with the carbon fiber down tubes and their fixing bolts with all the folding hinge assembly comes out at 1.20 kg.
Look at https://newatlas.com/bicycles/one-off-folding-bike/