There's a thread on bikeforums.net talking about this bike, too.
http://www.bikeforums.net/showthread.php?t=276090

I discovered this bicycle design through the comments of the designer Alessandro Belli on hubpages.com. He sets out the advantages of his design:

http://hubpages.com/hub/A-Bike_folding_bicycle_review

Some amusing comments in the Digg article on it here:

http://digg.com/gadgets/4kg_All_plastic_bicycle_invented_The_future_of_transport#c4306902

Garry

What's interesting is that it uses existing composite technology. Whether it can be manufactured economically is another question.

The designer has stated that it's as stiff as a normal bicycle, I am sure many would like to have a test ride to find out for themselves. Somehow, I think the suspension bridge like cables might have something to do with the stiffness of the frame.

He also states that it folds to a smaller package than the A-Bike.

It's obvious that we have to drop conventional materials used in bicycle construction to get the weight down for a folding bicycle. I wonder how many years it will take though.

I heard carbon nanotubes hold the key to producing composites up to the job. It has already been used experimentally in a carbon fibre bicycle frame. As stated in Wikipedia:

"In 2000, a multi-walled carbon nanotube was tested to have a tensile strength of 63 GPa. In comparison, high-carbon steel has a tensile strength of approximately 1.2 GPa."

http://en.wikipedia.org/wiki/Carbon_nanotubes

I read somewhere that they should be able to produce a composite with a tensile strength over 100 GPa.

This is very exciting! It looks quite nice and the wheels are bigger than A-Bike. I actually think the weight is more important than the absolute size, as even Bromptons can quite happily go onto trains and buses.

Some people even have so called laptop computers that weight 4kg, hehe :lol:

Garry

Keep an eye on the minimal vehicle project. A 4 kg plastic bicycle design that has reached prototype stage. It just needs some major investment to get it manufactured:

http://www.ticona.com/index/news/newsletters/ticona_highlights_0105_lightweightbicycle.htm
http://www.minimalvehicleproject.com/

I heard Sinclair is also looking into developing an all plastic bicycle, but it would require a different composite than that used in the current A-Bike.