bluefoxicy

https://www.masterlocks.com/product/4...eve,327,20.htm

Boron carbide and titanium with a hex link. I use a Master Lock Magnum with a Kryptonite cable lock, but I've been considering a high-strength chain. This is long enough!

Sure, it's expensive; but bolt cutters supply an 80:1 mechanical advantage. 30,000 pounds of cut strength? You need to put 375 pounds on the bolt cutters to cut this.. that means wrap a chain around the bolt cutter handle, padlock it, insert a breaker bar through it, and then twist the breaker bar to torque it down until it squeezes hard enough to cut the bolts. This assumes your bolt cutter doesn't break in the process.

To defeat this chain, you probably want a rotary tool or an angle grinder.

My only issue is I now use a 7 foot Kryptonite Flex which I could probably cut with a butter knife ... it's longer than the 5'6" chain lock. That lock's too short and I don't really want to drop my front wheel every time I lock it up, or carry a U-lock to lock the back wheel to the frame. Master Lock sells U-Locks that apparently break bottle jacks (takes over 3 tons of force to break the lock itself; floor jacks supply 1.5 and up), but I don't know if I could thread those through the chain links. At worst I'd need to lock up the chain, then loop it through the U lock, defeating the purpose of looping it through the U-lock anyway!

Also: pricey.

Fenway

Someone would cut the lock linking the ends of the chain together rather than the chain.

bluefoxicy

That's the problem I have now. My cable is a $12 Kryptonite Flex, my lock is a Master Lock Magnum. The Magnum can't be cut by hacksaw, and takes so much force with a bolt cutter that you'd break the bolt cutter. The cable ... can be cut with cable snippers.

The chain here is the same kind of material; you need an angle grinder to cut it. The lock I have is of the same stock; and the U locks I'm looking at require about 3 metric tons of force to break the locking mechanism itself, much less the shackle or the lock body. For reference, a decent floor jack supplies 1.5 tons of pressure or higher, while a bottle jack supplies considerably less. You can break a bottle jack on some of these U locks without defeating the lock itself.

Someone is more likely to saw through my frame and wheels.

NightShift

Don't kid yourself about needing an angle grinder. I cut. Kryptonite U lock off in less than a minute with a 1" cutting disk on a dremel. And isn't the Magnum one of the (many) Master locks that can be popped with a soda can shim?

I had my Diamond Back locked up with a heavy chain. When I found my bike had been stolen there were tool marks on the chain, but it was intact. The lock was smashed to pieces. The bar and latch mechanism were very durable, but a good hammer hit (or several) broke the pins that held the body together, and the body held the latch in alignment.

You may be able to discourage most people, and slow some people down, but don't start thinking no one can beat your setup. Especially if you're using a Master lock.

Doug5150

It looks and sounds like the one that Kryptonite sells, except for being a bit longer (5'6" vs 5' for the Kryptonite chain).
There is also the square-link chains, Kryptonite uses that for another lock, and Abus sells what appears to be the same chains in Europeland.

The Kryptonite one is hardened steel with a special tool-resistant metallic coating colored straw-yellow.
I suspect that the Master Lock chain above is the same, since boron carbide can only be produced in flat sheets (which is why military vehicle armor is always made of flat sheets) and Titanium would cost way more than that (titanium costs about 10X what most typical grades of steel do).

The Kryptonite New York/Fagheddaboudit lock is around $110, for both the 5' chain and a lock.... So spending $80 just for the chain doesn't sound like that great of a deal, when the better locks all cost $60+ bought separately.



And as much as I might sound like a shill for Kryptonite, I can assure you I'm not. As I browse Amazon, I see that they have taken to putting their names on all sorts of cheap junk locks now. :|

bluefoxicy

Yes, that would be a power tool. If you can get power out there and a power tool, you're playing a different game than bottle jacks and bolt cutters. An angle grinder is cheap and plugs into the same socket as a rotary tool.

Yes, my current lock is a spring-compression type shackle latch. The soda can shim is an obvious technical bypass, but most people want to try bolt cutters. For what it's worth, I also have a Magnum that uses a slide-in latch, but you can't lock that without the key: you turn the key one way to unlock, remove the lock, and then you put the shackle back and turn the key the other way to slide the latch into place and lock the lock. The barrel is fixed in either the open or closed position, and will not release the key in any partial position; it also will not turn without the key once it's in one of those positions. That particular lock has no specific weaknesses; it is a pin tumbler lock subject to the same weaknesses as any barrel-type pin tumbler, taking into account any additional security mechanisms.

The U-lock I want is a rotary disc lock; unfortunately, I don't know if that means it's actually a disc lock or if it's a mislabeled wafer lock. Wafer locks are surprisingly easy to pick, even easier than a regular pin tumbler lock. Disc tumbler locks are ... not easy to pick, at all, and so people attack other aspects of the lock because it's generally easier than picking a disc tumbler lock. Unfortunately, many companies label wafer locks as disc tumbler locks, because they are stupid. The key itself is barrel shaped, and a wafer lock is a regular type of pin tumbler lock made even more poorly, so I'm guessing it's legitimately a disc tumbler.

I don't know what its latching mechanism is, though.

https://www.masterlock.com/product_de...ikeLocks/8196D

If you have any suggestions on bypass mechanisms for this I'd be interested. If it's a spring-based locking mechanism, i.e. locks without having to turn the key, then obviously it has a shimming weakness; it's impossible to ward this kind of shackle design, short of making the bite into the shackle deep and making the tip of the shackle a chisel tip to meet with the locking pin and guide it on (that way you're able to expose a flat edge to the shim, preventing horizontal motion from vertical force, as you can have the locking pin slide pretty much all the way through the shackle if you like).

Still, these are things the average bike thief won't have handy. For most of the clean bypasses like picking or shimming, that's mostly a matter of patience (although both can be quite fast) and technical knowledge. Otherwise, we're talking about bolt cutters and bottle jacks; even hacksaws are a ridiculous attack scenario, takes too friggin' long.
Yeah, that's why I want to lock up the chain with the U-lock ... it's a different locking mechanism and takes some 3 tons of force to break the lock.

No one relevant. Really who cares? It's way too much effort; bolt cutter the next bike and let's get going dude.


Boron carbide ceramic can only be produced as flat sheets; this is boron carbide steel, a steel alloy of iron, carbon, and boron, in which the boron reacts with the carbon to produce carbide compounds. Steel is often hardened by carbide ceramics; it is often somewhat brittle, hence why a U-Lock is made from hardened steel that will get mangled out of shape, rather than high-carbide steel that will simply shatter under excessive force from a bottle jack. Of course, you can make the arm of a U-lock pretty thick, too...

NightShift

A rotory tool is a power tool, but not in the same class as an angle grinder. They have less torque/cutting power, but are smaller, quieter, raise fewer questions if you're found carrying them, and come in very portable battery powered versions that are more than up to cutting through a U lock.

How many bike thieves use bottle jacks? The typical tools where I come from are pocket snips, bolt cutters, and pry bars.

The problem with locks that can be opened with a soda can shim or a bic pen is not that every bike thief will know and exploit the trick, it's that the tricks are so simple and the tools so accessible that your bike becomes a target of opportunity for anyone of low morals who knows the trick. And that's enough people that your bike is just as likely to be stolen. Or maybe they'll just steal the chain. Anybody remember the guy who was busted because he covered one whole wall of his bedroom with The Club?

I don't know any specific vulnerability of the U lock you linked, but given it's a Master lock I have to ask how many different key patterns do they use? This isn't anywhere near as much of an issue as the shim vulnerability but Master lock does have a reputation for having a very small number of master keys for each series of locks.

If you can run the U lock through the links of the chain it should be a pretty effective setup.
Personally I use a Brinks shrouded contractors padlock. Getting The lock closed through two links of the chain took a little practice, but there's no room to fit any kind of tool in between (seriously couldn't use a hacksaw in that gap). I don't know the spec of the chain, but I can't cut it with 3' bolt cutters and it was cheap from Ace Hardware (covered with large water filter tubing [heat shrunk] probably not as light as what you're looking at).

bluefoxicy

This is hilarious. Less hilarious was the guy that made a habit of stealing stop signs; he was arrested because people died, otherwise the police somehow never thought to bang on his door and ask why his back yard was a stop sign farm.

Interesting stuff. Anything that resists 3 foot bolt cutters is decent, although I think 30,000lb is break force. If I chained the bolt cutter handles together and then used a prybar to force it together by twisting the chain, either the chain or (probably the handles on) the bolt cutter would fail before the actual lock failed. But yeah, the casual thief isn't going to try to MacGuyver his bolt cutters because he can't squeeze hard enough; he's just going to steal the next bike, or try them on the lock.

Doug5150

I still don't see that the Master Lock chain is anything special. The specs at the link don't get very particular, and a few other companies sell square- and hex-link expensive security chain that looks very similar.


Here's a thought: why not just get two decent-brand U-locks for ~$60 each, and use one on each end of the bike?
Less weight, easier & faster to use, and (very likely) still makes your bike twice as difficult to steal as every other one.

I have a Kryptonite 5-footer--and as I said, due to the weight alone, I only bring it when I know the other lock (Master Lock Street Cuffs) won't work.

NightShift

Oh, hey, the Master lock cuffs are great, in theory. Are the ones you have the kind that can be opened with a pen?

The chain can be used for things a U lock can't, like locking a mountain bike to a tree at a camp ground.

Doug5150

The Bic pen trick won't work on the Master Lock Street Cuffs.

NightShift

To be clear the pen trick worked on the original street cuffs, but not the new ones.

Doug5150

I have a pair of the original Street Cuffs, bought before the Bic pen trick went public. It never worked on them. The key is a regular-style barrel key, but the lock is built different.

A few people online claimed that they opened theirs with the pen trick. I would bet that all of the people who claimed this were thoughtfully trying to inform the public, and (since it used barrel keys) were lying about a product that they had never held in their own hands. There's probably a way to pick the lock somehow, but a plain bic pen (or pen cap) won't do it.

People who owned them tried it and found that it wouldn't work. If you have one to play with, you can easily see why it won't work. Despite a lot of wrongly-informed customers getting pissed off about it--Master never offered any refund or exchange program.

Most of the bic-pen videos are dated 2004, and yet Street Cuffs still come with barrel keys even today:
https://www.masterlock.com/product_de...ikeLocks/8200D



To this day I wonder how many people threw away their $50-$75 Street Cuffs because somebody else informed them incorrectly.

NightShift

Ok, I don't own a set of old Street Cuffs. Just did some Googling. Gotta ask, are you sure what you have aren't vulnerable to the pen trick? It sounds like Master lock announced they were not vulnerable to the "BiC" pen trick, and a few people said yeah, you need a wider tube. I can't test that, but I'd really like to know. Given the difference in how the lock is tensioned it sounds plausible.

Doug5150

On a normal barrel lock, the center post inside the keyhole turns when the lock turns (as it is being opened). The pen cap (the pen itself isn't big enough) has to fit tight enough around that center post to turn it, once you jiggle the pen cap to get the lock's pins clear of their slots.

On the Street Cuff locks, the center post does not turn at all. Once the key is inserted, the lock's mechanism must be turned by the ends of the pins themselves, and then the center post pops out a short distance.
You can shut each of the cuffs, but they don't really lock until you push that center button back in.

If the inserted end of the pen cap is flat, then it won't be able to grab the pins at all to turn the lock mechanism.
If the pen cap edge has a notch cut into it, then you won't be able to jiggle the lock pins nearly as easily, since one of them will always be lower than all the others.

Plus--if the pen cap fits too tight on the center post, then the center post cannot pop out, so it won't unlock for that reason either.


[edit added]
The main bad thing I have heard about the Street Cuffs is that if you use them a lot--locking and unlocking them several times a day--the locks will wear out relatively quickly compared to other styles of key/lock systems.

NightShift

So it needs to be wide enough to allow the center to move, and malleable enough to deform to the pins. What am I missing?

Yeah, I heard about the high fail rate. Not fun finding out your bike is locked up but you can't move it. And at that point it's harder for you to get your bike than it is for a bike thief (because you need transportation and they probably have transportation).


In any case I still say it's a nice idea, but the actual product needs some work.

You can get prison grade handcuffs with unique keys. They don't come covered in plastic to prevent scratching your frame, but a quick dip can fix that. I'll try to track down prices and ordering info.

Doug5150

What you are missing is--the actual experience of holding a pair in your hands, and trying to pick them with a Bic pen. It doesn't work.

Police-style handcuffs aren't really very pick-proof, they just depend on the prisoner not having anything suitable to even attempt picking the lock with.

NightShift

Well, I can't argue with the first part, but your response still leaves we wondering does it not work, or have you just not been able to do it?I don't mean that to be offensive; I've just never been convinced by the "because I say so" argument.

Police handcuffs are not pick proof, at all, and all use the same key, available at uniform shops for ~$1 a piece no questions asked.
That's not what I'm referring to. I'll try to find a link. That will probably be easier and more useful than explaining the difference.

NightShift

https://www.handcuffwarehouse.com/clmo101hiseh.html

NightShift

So, I finally got a chance to play with a set of Master Lock Street Cuffs, and I picked them, with a pen.
Ok, full disclosure: I used a pen tube, which I split with my pocket knife, and a curved sewing needle. And it took me more than 5 minutes futzing with it on a counter in a well lit room. But I'm not particularly skilled at picking locks.

Even with the barrel key locks that can be picked with just a bic aren't as quick and easy to open as some of the videos make it seem, but to me the Street Cuff locks don't seem like a huge improvement.

Looigi

I've been saying the same thing for some time. A Dremel and thin cutoff wheel goes through hardened steel very nicely and quickly. I've used it shorten the shank of a 3/8" steel drill bit in about 30 seconds. I also cut through the shackle of lock in a similar amount of time. I used a plug-in Dremel but I'm confident a battery operated Dremel would work nicely as well. They now sell larger diameter thicker wheels but I find these don't cut quite as fast.

Cutting softer material, like aluminum, is more problematic as it clogs the wheel.

fietsbob

I just Moved, instead .. out of the bike swiping College town.

enigmaT120

Which town? I ask because Corvallis is a reasonable days ride from where I live, if I don't have anything else to do that day.