It actually cheaper to buy a couple of expanding bolts and drill them into the concrete with a chain on each, then hammer the bolt heads so they can be unscrewed and lock the chain ends together. A real bastard also glues the thread prefills the hole with concrete-compatible glue, and uses expensive hardend chain. While there some value in a cover like the ones advertised, the gap between "I can defeat a chain" and "I can defeat the bolt head but not the cap or chain" is very narrow. I have the welder, but I just use bolts, it not worth fabricating something more complex Мסž Jul 6 '11 at 2:23

The replacement business for bike-light-brackets is part driven by people that get their bikes stolen to have the lights left behind. A large chunk of these bikes come from bikes stolen from garden sheds and garages. The jaundiced view of sheds and garages is that they act as convenient collection places for thieves. There is also the problem of people finding that th ... Read more »