Locks that work

This may be innacurate but I have heard tell that the most common way to steal a bike secured with a cheap D-lock is just to pick the bike up and rotate it- the leverage caused by the frame turning in the lock is enough to pop the cheap ones off.

it is, but unfortunately if the U-lock is pretty strong, then it will actually damaged the frame easily.

some forumeanger got their frame damaged by theft trying that trick, it only work well on a cheaper U-lock really.