I know this may sound stupid and reckless to some, but I never use anything other than a cheap cable lock. BUT I ALWAYS lock it. I figure that anybody who came over to my bike with TOOLS will eventually defeat all but the best locks. And a pro will get your bike even if you parked it in wet cement that is now hard! All I'm trying to do is prevent someone from easily hopping on my bike and using it as a ride home. Of course I live in a low-crime suburban area.