There is a thread going on in our forums discussing the best bicycle lock to buy to prevent bicycle theft. Here is a nice little video we had seen before in which an “ex” bike thief shows how well bicycle locks work. The “ex” thief concludes that no lock is going to stop a thief, but a hardened steel one is the best. Get your hardened steel on, Venice!
The only bicycle lock we know of that works well is to park it where you can see it.