I’m keen on bicycle design: especially features which keep machines’ handlebars in the hands of their lawful riders.
I once had a bicycle which wouldn’t fit into my van on the day we moved house, so I had to leave it behind. A small experiment saw it parked, unlocked, on a local thoroughfare to test how long it lasted before being stolen. The answer was less than one hour and this from within a forest of many other, fully-locked bikes.
It seems crazy to me that riders have to carry around extra legirons and chains and padlocks just to secure their steeds. Why not use the metalwork of the bike itself to help lock it up?
Today’s invention is to create a bicycle with a removable cross bar. With the bar absent, the bike is rendered unrideable, given that it would immediately bend and break. Each bar would have a large mechanical slot at one end, attaching it securely to the rest of the frame. At the other end, the bar would have an integral key mechanism, allowing only the bike’s original bar to be locked in place.
A bike owner, on leaving the machine, would detach the lightweight bar and take it with them (it would probably be used to hold the tyre pump internally, as well as a torch bulb inside one end). This would allow them to leave the bike anywhere, without needing to secure it to anything.
If you were the paranoid owner of a very expensive machine, you might choose to open the frame using the bar and lock it in place again but only after placing a telegraph pole through the triangular space.