bob13bob

https://www.bikeforums.net/*****************bRLA

No lock is safe when you provide a lot of incentive to steal your bike. Don't leave your high dollar bikes locked outside. Minimizing resale value is best way to deter them.

before someone starts espousing expensive locks, here's a kryptonite evo lock getting cut in 20s by an inexperienced lock grinder. I bet if you ground locks all the time you'd be a bit faster.
https://www.youtube.com/watch?v=rQpj6UhsMps

indyfabz

What's high-dollar to you? My LHT with $420 worth of racks attached to it gets locked up outside during the day (and sometimes at night, but never overnight) on a regular basis. In fact, I have been locking up relatively expensive bikes outside for damn near 30 years. Not one stolen yet, but I did have one stolen from inside my house while I was at home and awake.
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jefnvk

And cobalt drill bits in an 18V drill will chew up even hardened steel with ease.

Locks keep honest people honest, and dissuade casual theft. If someone wants your bike that's locked up outside, nothing you do will stop them, short of hiring someone to sit there and watch your bike 24/7.

My favorite story was told to me in the Netherlands. The storyteller had bike stolen when a group of thieves dressed up like the city officials whose job it is to remove illegally chained bicycles, and went down a street and cleaned it out of anything of value. No one questioned them, because they looked official.

dim

thats what they do here in Cambridge UK (in broad daylight), and no-one bats an eyelid. Thieves even travel from London by train to Cambridge to steal bikes. (you can take bikes on some trains from Cambridge to London)

There are over 30 colleges/universities here and thousands of bikes all over the place.... some rich students with expensive bikes

Hoonigan

That's crazy. It's amazing how many folks walked or drove by and nobody said anything until the girl at the end. I bet nobody even called the police.

Krazy Koz

While there is no disputing the facts of what was demonstrated in either video (that power tools can defeat any bicycle lock in a relatively short amount of time), I do think the conclusion that bicycle security isn't effective, worth investing significantly in, or is in some way futile is an incorrect one (or at least, myopic). Forgive me if I am interpreting the poster's intent incorrectly, but these kind of posts end up on the forum with some regularity and that seems to be the tenor of those, by and large.

In the case of the first video, despite the fact that it shows the thief not being disturbed and getting away, if you watch to the end, you also see a number of people talking about it, at least two of which got a good look at the criminal. Just because a person gets away with the bike, doesn't mean that they get away with the crime. Also, the stolen bike did not seem to be locked well. While I can't speak to the quality of the lock, I can say that locking the bike by the top-tube is a bad idea, as it makes all manner of attacks easier (not just power-tools) by giving the thief more room to attack the lock without damaging the bike. It also makes leverage-based attacks much easier. This is one of the reasons that anybody using something better than a cable lock should attach the lock to a wheel and either the front or rear triangle, because it gives thieves much less room to work or insert tools.

In the case of the second video, the person had the u-lock immobilized in a vice. Out in the world, a lock will move when attacked with any kind of tool, which will make the process slower, especially if it isn't attached to the top tube, thereby making it is harder to access. Also, certain kinds of locks, such as chains are resistant (albeit, not immune) to power-tools, because they move easily and are harder to apply consistent force upon.

The vast majority of thieves are opportunists and usually carry nothing more sophisticated than a pair of diagonal pliers, a screw driver, and a few other simple tools. Anything above and beyond a cable-lock (which are still sadly omnipresent(!) at Ohio State University, which I live near) or an extremely cheap u-lock will stop them. Professional thieves are far more rare and from my research tend to steal bicycles during the night, often breaking into the garages of upper-middle class homes to do their work. There was an excellent article about bicycle security that featured interviews with actual bike-thieves that was published a few months ago. I highly encourage y'all to take a look - it's a fun read.
The Best Bike Lock | The Sweethome

All that perorating out of the way, I think that the 10% rule is still a good one, with the caveat that commuters are well-served to buy insurance in addition to any locks they may carry. I've been locking my bike overnight for a few years now at a hospital in a not-so-great part of town with no thefts or evidence at all that my bike has been molested in the slightest. Then again, Columbus is neither San Francisco nor New York.