Originally posted by pjv Please explain.
The minimum mass for a UCI (Union Cycliste Internationale) road race legal bicycle is 6.8kg. They're talking about lowering that limit, but have not yet done so. The lightest bike that I'm aware of is the AX-Lightness VIAL evo ULTRA which pulls the scales at 4.4kg. And, that costs about $15,000.
The problem therefore is that these ultra light bikes cannot be used in any UCI event and, subsequently are excluded at many club races which, in turn, use the UCI rules as a basis for their club rules. Some road bikes are slightly below the limit and they fix the problem by using heavier components to get over the 6.8kg (15lbs) limit.
Then, there's also rules for the bicycle geometry. It could be argued that the single chain stay / seat stay asymmetric design seen on the Bugatti bike may not comply either.
So, sadly, these technological masterpieces can be used on the road, but not in (most) races and for the sort of money, that makes them a very expensive hobby use bicycle.