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How do thieves cut locks??

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Old 05-04-06 | 05:29 PM
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How do thieves cut locks??

After buying a thrift store bike with a lock permanently attached to the seat, I set out to cut the lock and cable off. This proved to be a difficult endeavor. The lock was a Masterlock key-type, the kind that locks fenses and industrial doors. So that wasn't coming off. Cutting the cables was the answer, seeing as it was the thin braided type in a black plastic sleeve. The braided steel cable was about 1/4 of an inch thick, pretty thin. Seems easy, right?

Tools attempted:
wire cutters (small)
hacksaw (large)
industrial strength bolt cutters (large, 2 foot arms on each, blades were dull from cutting tree branches so I sharpened them with a knife stone and they still wouldn't cut through )

The final tool attempted worked. A dremel tool with a small 1/4 inch circular grinder/saw attachment, used at the end of the cable where I pulled the plastic sleeve back. The saw sent up sparks three inches in the air each time it made contact with the cable. After a couple minutes of gingerly cutting at each side of the cable, it finally gave way.

If you ever see some dirtbag hovering over your bike with sparks arching up like he's welding, he aint welding. He's stealing your bike. A battery powered version would do the trick, but it's going to take a couple minutes to complete. If it was a cable any thicker than 1/2 an inch, forget it, I can't picture a way you can cut it. So good news to those of us with good locks and cables
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Old 05-04-06 | 06:01 PM
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Old 05-04-06 | 06:14 PM
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There are wire cutters, as you used, and there are cable cutters.

Cable cutters as below with a scissor action will slice through cable locks like string.
Take your 1/4" cable to a bike mechanic and ask him to cut it with his park or shimano cable cutters.

Also "industrial strength" bolt cutters do not get dull by chopping tree branches (). My bolt cutters were purchased by my Grandfather in the late 1950s and they still work perfectly. They have an unusual double lever action and are barely over a foot long and have been used to rescue friends who have lost their keys on a number of occasions.

Just because you don't have the tools, does not mean that thieves don't. Anybody with elementary metalworking skills is going to be able to bust your lock faster than you can open it with the key.
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Old 05-04-06 | 06:34 PM
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Old 05-04-06 | 06:38 PM
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a buddy of mine forgot his key prior to a big ride. His bike was locked to his truck. It took me maybe 1minute to cut through the cable lock with a hand held dremel.

Don't get cheap on your locks
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Old 05-04-06 | 06:47 PM
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Locks only key honest people honest!
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Old 05-04-06 | 07:22 PM
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Originally Posted by fastedddie
Locks only key honest people honest!
an amusingly fitting typo.


Yeah, locks of any variety are no match for the right tools.

cables
Thin ones can be cut instantly with appropriate tools. Thicker ones may need a grinding type tool, but I have heard that good bolt cutters can make short work of thick cables. Even if the cutters don't cut cleanly through the cable, they will more than likely sever enough strands that flexing the weak point back and forth for a minute or two will cause the remaining strands to break from fatigue. Fatter cables are somewhat better than skinnier cables, but really no cable is secure with a desirable enough bike when it all boils down.

chains
cheap hardware store chain can be lopped with fairly small bolt cutters in a hurry. Better hardened chain, up to an including the kind of stuff Kryptonite and others use for their top-of-the-line chain locks is no match for an angle grinder and a few minutes of undisturbed time. If you must use chain, get the real deal hardened chain with the fattest links that you can carry.

padlocks
See above, since a padlock is really just a glorified link of chain that opens and closes at the will of it's master. This applies to all varieties of padlocks, from combo locks to keyed locks to whatever. Also, a lot of padlocks will give up the ghost if you whack them hard enough with a big hammer. If you must use a padlock, try to lock your bike in a manner where the padlock is suspended up away from the pavement or other hard surfaces to make a hammer attack much less feasable. Also, avoid flimsy little locks in favor of a beefier padlock.

combo locks
Anything with a combination is instantly vulnerable to means that involve no physical harm. $10 four-dial combo cable locks can usually be opened in under 30 seconds by someone that has half a clue what they are doing. These are not secure at all. Even better combination locks are 100% vulerable if a thief has enough time and patience to methodically work through the possible combinations. If you must use a combo lock of some variety, choose one that is least likely to be vulnerable to brute force (trying all the combinations) and manipulation (feeling beside number wheels with a thin piece of metal for grooves) attacks. Combo locks seem like a pretty bad idea to me in general.

keyed locks
If combo locks are bad, key locks are better, right? Only maybe. Remember the Bic pen vulnerability a zillion Kryptonite U locks turned out to have? Case in point. That aside, many keyed locks are not hard to pick with the right tools, and a pro can open most typical locks in less than a minute if he/she wanted to. Even if you do get a very invulnerable keyed lock, you are still at the mercy of the cable or chain or whatever else is a part of the locking system.

U locks
These have been around since the 70s, and were a bit of a revolution. They have their fair share of quirks too. On some models, the key goes into the end of the straight part, which then has to be longer to accomodate the locking mechainism. Thieves discovered that they could simply snap off this protruding stub with a piece of pipe and defeat the lock. The solution was to put a plumbing tee fitting over the T formed by this intersection of the lock to make it inmpossible to get a purchase on the lock. Modern models are much better designed, with the notable exception of the Bic pen vulnerability to the round key locks. The other major vulnerability of U locks in general is that of force. Thieves can crack most U locks wide open by levering inside the closed lock with a car jack. The best bet around this is to use the smallest U lock that works for you to leave less room inside the U for a jack to be used.



Overall, there is no good solution to locking up your bike. Locks are merely a deterrant, and one that works best when supplimented in various ways, such as by locking up your bike near much more expensive bikes, making your bike visually less appealing, or just riding a crappy bike that few people would want to steal. If you do have an exceptionally theft-worthy bike, lock up with several different kinds of locks. A good U lock, a chain, and a good keyed padlock is a decent combination. A thief would most likely need several different tools to defeat each different lock, making the bike less desirable compared to some road bike locked up next to yours with just a cable.
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Old 05-04-06 | 08:48 PM
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so whats the best solution, multiple locks?
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Old 05-04-06 | 09:01 PM
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Originally Posted by Eriol
so whats the best solution, multiple locks?
Yeah. Use two different locks, that means anybody with an intent to steal your bike must bring two sets of tools. I use a U-lock / combo lock setup. The combo lock doesn't do much but act as a deterrent. The U-lock is great, though.
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Old 05-04-06 | 09:06 PM
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Originally Posted by Eriol
so whats the best solution, multiple locks?
The best solution is to get a folding bike to take with you.
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Old 05-04-06 | 11:17 PM
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The best solution is to buy a monkey, give him a Steyr Scout rifle, and train him in sniper training.

Keep him in a special pannier bag on your rear rack, and give him plenty of bananas...and don't forget taking him to the zoo for the occaisional booty call, never irritate a monkey that can pick you off from 400 yards.

....when you need to secure your bike, let him do his job.

Simian Security, for times when you just gotta go bananas on a fool.
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Old 05-04-06 | 11:27 PM
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Originally Posted by catatonic
The best solution is to buy a monkey, give him a Steyr Scout rifle, and train him in sniper training.

Keep him in a special pannier bag on your rear rack, and give him plenty of bananas...and don't forget taking him to the zoo for the occaisional booty call, never irritate a monkey that can pick you off from 400 yards.

....when you need to secure your bike, let him do his job.

Simian Security, for times when you just gotta go bananas on a fool.
https://www.trunkmonkeyad.com/4wmv.htm
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Old 05-05-06 | 07:41 AM
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There is practice that I recommend. If the possibility exists, lock your bike close to a decent looking one with less security. If an itinerant thief happens by then the other bike will be the obvious choice for a quick reward.
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Old 05-05-06 | 08:57 AM
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Cordless right-angle grinder. That's what locksmiths use. You can take about anything off in 60 seconds.
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Old 05-05-06 | 09:11 AM
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yeah... locks are a deterrent, thats all. Baically, just take your bike indoors with you, thats the only safe way. There is no way I am locking up my $2000 peice of machinery outside.
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Old 05-05-06 | 01:51 PM
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Originally Posted by ItsJustMe
Cordless right-angle grinder. That's what locksmiths use. You can take about anything off in 60 seconds.

There are locks, and then there are LOCKS. The editors of "Cycling Plus" test bike locks once or twice each year. Crummy locks (all cable locks, and most chains and u-locks) can be opened in ten seconds to sixty seconds.

However, their editors have found that even using expensive, noisy power tools, the best locks take over ten minutes to open. CP found a couple of padlocks that their power tools could only scratch. And, they found a couple of chains that could not be cut. However, no company matched the "cut proof" padlock with the "cut proof" chain. So, to get the ultimate in protection, a customer must match a padlock from company "A" with a chain from company "K".

Likewise, the very best u-locks, such as the Kryptonite New York lock, can defeat a skilled crook who is using power tools for at least ten minutes. In my neighborhood, a theft using power tools is unheard of. But, I suspect that is someone was silly enough to leave a $2,000 bike at the same location, day after day, sooner or later, a crook would invest in the appropriate power tools.

If you are going to leave a bike locked in public at a large university campus, or in a big city, you need a couple of serious and expensive locks. And, those locks should be attached to a bike that LOOKS like it is worth only a couple hundred bucks or less (although it may be worth much more). If you leave a Trek Madone alone for long, it will soon be someone else's bike.
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Old 05-05-06 | 02:52 PM
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The best bet for a campus bike is the ugliest bike you can still ride.

I used an old girls framed, basket on the front, SSpeed rusted piece o' crap for a number of years and didn't even have to lock it on campus. In fact a lock might have given it some value.

This thing looked like it had been long abandoned... which was exactly the look I wanted. Mechanically it was in perfect shape... but when I overhauled it, I took pains to not clean up any of the outside. The chain would have been the give away as it was new and in well oiled condition... but no one could see past the bent rusted basket on the handlebars, not to mention the crappy chainguard.

My commute was about 4 miles either way... and one good hill...

In the end, I "sold" the bike to a co-ed on campus for a 12pack of good beer.
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Old 05-05-06 | 03:18 PM
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Originally Posted by alanbikehouston
So, to get the ultimate in protection, a customer must match a padlock from company "A" with a chain from company "K".
Well-said!
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Old 05-05-06 | 04:08 PM
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Originally Posted by alanbikehouston
However, their editors have found that even using expensive, noisy power tools, the best locks take over ten minutes to open. CP found a couple of padlocks that their power tools could only scratch.
Would like to read the entire article, but couldn't find it.
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Old 05-05-06 | 05:02 PM
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combo locks
Anything with a combination is instantly vulnerable to means that involve no physical harm. $10 four-dial combo cable locks can usually be opened in under 30 seconds by someone that has half a clue what they are doing. These are not secure at all. Even better combination locks are 100% vulerable if a thief has enough time and patience to methodically work through the possible combinations. If you must use a combo lock of some variety, choose one that is least likely to be vulnerable to brute force (trying all the combinations) and manipulation (feeling beside number wheels with a thin piece of metal for grooves) attacks. Combo locks seem like a pretty bad idea to me in general.
The combo locks with 4 dials normally have 10,000 possible combinations, so if you can try one combo and move on to the next in 1 second, you're talking 1 hour and 20 minutes to try half of the possible combinations.

But a person who's good with combo locks can probably figure out the combination in a minute or two.
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Old 05-05-06 | 05:49 PM
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I usually take off the front tire if I can, or I pull the seat off and take it with me (assuming you have a quick release clamp). That usually makes it more un-appealing to steal. Plus lock it somewhere really public if you can, where its obvious when someone is using an angle grinder on it.
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Old 05-05-06 | 07:09 PM
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Originally Posted by cerewa

But a person who's good with combo locks can probably figure out the combination in a minute or two.
How they do it?
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Old 05-05-06 | 07:17 PM
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https://web.archive.org/web/200411290...ster_lock.html
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Old 05-05-06 | 07:39 PM
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hmmm, interesting
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