Thread: U-Lock?
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Old 06-08-11, 12:25 PM
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bluefoxicy
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Originally Posted by chibibike View Post
no chains are not good unless it's some uncommon metal that can't be cut.
U-locks are made out of metal too, so if the chain can be cut, so can the U-lock. You can make a chain harder to cut than a U-lock; the typical U-lock attack is a bottle jack, which as I said will crack the metal a high carbide chain is made out of but fail to a softer and more malleable metal. Of course, the softer metal of a U-Lock is more vulnerable to abrasion attacks and thus cutting discs on a power tool, whereas a high carbide steel chain will resist power tools for several minutes.

This issue is more of what U-Lock to get. Kryptonite U-Locks range from "Bust with a bottle jack" to "Busts a bottle jack," or so I'm told. You can shim some types of shackle locks (the spring-loaded ones Master Lock uses are the standard for a lot of padlocks; the Kryptonite high-security U-locks use dead bolts, which I interpret to mean you have to turn the key to lock them, sliding a bolt in place... shim won't work). Cheaper U-locks like you get at Wal-Mart can be cut with a 47 inch bolt cutter, good waste of $20 there.

Then there's locks themselves. Various types of barrel keys have various attacks, from Bic pens to hollowed barrels (the barrel is always hollow, but if you cut slots on the key points and fiddle around with paper clips you can twist the lock while doing regular old lock picking). Combination locks have various flaws from being able to see the pins to jamming at the correct combination under pressure, so you pull the shackle tight and roll the numbers from the last one back and it sticks at the right combination. The primary defense mechanism of dial-type combination locks is the use of false tumblers, which you can detect through various methods, allowing for a vanilla stethoscope attack.

I have lifetime protection against rubber hose lock picking. The rest requires a lock that's simply not vulnerable to those attacks. I don't have a defense against power tools--even high-carbide steel will cut eventually from a rotary cutting disc, despite being difficult to machine.

The $20 mini U-lock from Wal-Mart isn't going to be as secure as a properly made U-Lock that may cost 4 or 5 times as much. Then again, Mark Tobias showed that a $50 Kryptonite U-Lock failed in 3 seconds against a Bic pen; you paid for a name, not a lock.
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