Originally Posted by
mechBgon
Whichever way you decide, it's good to do like Sixty Fiver shows, and get your lock's shackle filled up so there's not room to put a jack in there.
That's the key to making a u-lock work alright: the way the good ones get broken is by a thief using a bottle jack. But the jack has to be inserted inside the U. If the space there is filled the lock is at its most effective.