Can't really think of a dumber material to make a bike out of - maybe silly putty? Carbon fiber, yes. Titanium, sure. But gold is heavier than lead, and not much stronger. If it really is made of solid gold (not just plated over steel or aluminum), it's going to collapse the first time anyone tries to ride it. (Indeed, I'm surprised it can support its own weight.) But they won't get far: it's a tossup whether the chain will break, or the teeth strip off the chainwheels.
