The U-lock had better watch its back now that the Vier Lock has been designed. This bike lock is designed to be just as strong as a U-lock but is much easier to transport. Its killer edge is that it can be disassembled into four pieces, with the makers saying the pieces can fit into a bag the size of a burrito. The bag itself can be strapped to your bike seat for easy portability.
Although it can be disassembled, the Vier Lock is no softie. The makers tested it and found that it has 1.5 tons of pull strength. The lock is currently seeking funding on Kickstarter, where a pledge of $65 will secure you a lock.