Originally Posted by
agent pombero
Nowadays one can get a battery powered angle grinder and go to town on any u-lock on the market. No lock is 100% secure. The best defense is to bring your bike inside wherever you go or to not bring it at all.
There are some padlocks made in ceramic like the sargent & greenleaf 951C padlock that greatly reduce the action of battery powered angle grinders or at least that what they said but unless you plan to secure one spoke i don't see what you can do with it alone.
A lock can be 100% secure if it is able to handle the attack of any thief more than the time you leave your bike there. So if you never leave your bike more than 2 minutes and that your ulock requires more than 2 minutes to be defeated then it is 100% secure. But it doesn't mean the rest is. In real life who would leave a bike only 2 minutes.