I've been looking into the different kind of locks available, and came upon this short documentary about bike thefts in London. Seems that just about any lock on the market can be easily beaten by a large enough set of bolt cutters. So I was trying to think of a better system, and I thought of something: Why not have locks that are built into the bike itself? Something that locks out the drive train in some way?
It seems that in the majority of thefts, the thieves are riding away on the bike. From about 10 minutes of pondering the question, it seems like a small hole could be placed in the crank axle without compromising the strength too much, and then you could incorporate the locking mechanism into the down tube. When the bike is locked, the cranks can no longer turn.
Searching on the internet yielded no results for locks that lock the drive train of the bike. Is it just an unworkable idea, or has nobody thought of it until now?
You would still have to lock the bike to a rack to ensure that someone doesn't just carry it away or put it on the back of a truck. But it would make the bike that much less of a target if the thief knew that such a system was in place.