Paranoid.Guy

I've long wondered about this.
The disadvantage of the U-lock over the case-hardened square/pentagonal/hexagonal section security chain is that the U-lock is vulnerable to leverage attacks with car jacks and long pipes. Both of them are susceptible to angle grinders, but that's the weakness of all locks.
So, which of them do you think is better?

johnny99

For maximum security, cops recommend using two different types of locks. Crooks are unlikely to be carrying tools to beat both types.

If you do use a chain alone, get a thick one. Some hardened chains can be snipped with bolt cutters.

You can also use a smaller U-lock that does have space for a car jack.

Jaywalk3r

It depends on what tools the local thieves carry. No lock will make your bike theft proof.

My personal rules of thumb: 1. Lock bike next to a more expensive bike that is not as well secured. 2. In high theft areas, use two different types of locks that are defeated with different tools.

The same bottle jack that will make short work of your U-lock will be useless on your chain (unless your chain is very short), but the U-lock will probably not be vulnerable to the tools that can defeat the chain.

Nightshade

Full coverage insurance trumps any stinking bike lock!!

fietsbob

folding bike : take it in with you.

Paranoid.Guy

Thank you for your suggestion.
Honestly, I've never thought of the security advantage of the folding bicycle. If one owns such a bike, they need no lock for it. It's probably very easy to fold it and put it in your backpack.
The problem: not everybody has a folding bike, nor do I.
What are the tools that could defeat a good bolt-cutter-proof security chain?(except the angle grinder).

Top Gunner

Between chains and u-locks (good ones), it's just a matter of preference. Chains are more versatile, but they are quite heavy. U-locks have limited locking options, but they are easier to carry. Either one can be defeated by some tools and not by others.

Personally, I prefer U-locks. I use a 2 lb mini U-lock for general use. I use a 4 lb U-lock for more theft-prone areas. Most decent chains weigh at least 8 or 9 lbs, and I have never had difficulty finding something secure to lock my bike to with a u-lock, hence my preference. Also, I have locking skewers on the wheels, seat post, and head, which makes things easier. Sometimes I use a 4' loop cable around the front wheel, for that added appearance of security, though it's not really necessary.

dougmc

It's not so easy, and they tend to be heavy, even heavier than a non-folding bike.
There is no such thing as a bolt cutter proof security chain -- some just need bigger bolt cutters.

But a dremel with a cutting wheel could probably get them off pretty easily. (It's a lot like an angle grinder, of course.)

Do not rely on anything but a U-lock to keep your bike safe for any length of time. It needs to be a good quality one, and ideally it's a small one so a jack won't fit inside. A cable lock is nice for protecting wheels.

fietsbob

I have a brompton, but not able to take it in with me , But I live in a rural town.
I use an armored cable lock for those occasions that I go in restaurants..

my newer bike , Friday, I have An Abus link Lock that I combine with the armored cable lock .

the hardened square steel link stuff is good. Bike #3 has a light weight version integrated with a frame mounted ring lock, that allows both wheels to be locked up and the chain around stuff.
It works ok too.. so far so good.. ring lock is always there , so no excuse for inconvenience
or having a roll off theft, then.

square link is harder to cut due to the geometry of the bolt cutter..

I recall seeing a you-tube thing where someone opened up the base of a streetlight ,
and used that power to run their grinder, and were left alone to do it, in New York City..

this town is a long ways from there..

Paranoid.Guy

One month ago or so I watched video clip on YouTube with a guy cutting several security chains with a large bolt cutter. The chains looked quite hefty, but most of them took less than a minute to cut. Apparently, the Kryptonite Fahgettaboudit chain was one of the easiest to defeat. Most chains shown there made a loud explosion-like sound and emitted a lot of sparks when the bolt cutter finally snipped them, but the Kryptonite chain did not. I'd link to that video but now I can't find it.

chivo387

I like the u-locks better but thats me.

wahoonc

• Folding Bike
• Ring Lock w/optional plug in chain or cable
• Ulock
• Big Chain
• Big Chain with a dog attached
• walk

Aaron

Stealthammer

The one tool any self-respecting bike will always carry is bolt cutters. Chains are useless.

Paranoid.Guy

tagaproject6

Wut???

Stealthammer

I use to clean up the bike racks at the end of the summer at a large university system to remove abandoned bikes. Chains and cables are worthless and take 5-10 seconds max to remove with a set of $20 bolt cutters, and U-locks never required more than a minute or two with $5 Toyota car jack, a customized 24" pipe or cordless angle grinder. You can keep honest people honest, but you can't stop a good thief. Chains and cables are just part of the Bike Thief 101 playbook and even a 14 year old kid can handle them on their first try.

AndreyT

A power grinder will remove absolutely anything. In fact, an ordinary hack saw will remove anything as well, it will just take longer. One can defeat any lock with a needle file, given enough time. This is understood perfectly well by anyone. So, there's no point to mention power grinders in this thread. There's no such thing as undefeatable lock and nobody's looking for one. The purpose of the lock is to:

1) Prevent casual walk-by thefts, when the thief simply grabs the bike as their own and rides into the sunset (or casually hooks it up on their car's bicycle rack), while everyone around doesn't even begin to suspect that something is wrong.
2) Impede thief's progress and turn the act of theft into a conspicuous act, when the thief has to use easily visible and/or noisy tools to defeat the lock. The point is to make people who witness the theft to either interfere or report it to police. In many cases the prospect of something like this happening will deter the thief.

If your bike is parked with no one around, then there's no way you can protect it from theft.

BarracksSi

Full coverage insurance won't get you ten miles home with twenty pounds of groceries.

A U-lock would be useless to me sometimes because I've had to lock up to light poles and trees. So, a good chain has become my default lock even though I have a couple pretty good U-locks.

americanlt2

I have a Kryptonite NY u-lock. I read a review that it would take almost 10 minutes to cut through. I plan on getting a bikeregistry chain also & looks to be tough. I live in Chicago where there are bike pro's so I need strong locks.

Bward76

I just use a leash attached to Ceaser!

NightShift

As has been stated security chains aren't "bolt-cutter-proof", but even if you can assume your chain will withstand the bolt-cutters most thieves would be using you still have to use something to lock the ends together.
A heavy chain and a shrouded contractors padlock is a fairly effective combo, but very very heavy. And with key locks there's always the chance someone will tamper with the lock so you can't open it (and most combination locks are ridiculously easy to open).

And to make you really paranoid I've seen two completely stripped frames still locked to bike racks, and one that was just missing the front fork (the front wheel was still locked to the frame).

Retro Grouch 

The first lock that you put on your bicycle, no matter how cheesy, is about 90% effective because it forces the potential thief to bring a tool with him.

As you move upward from 90% effective toward 100% effective you engage in a progressively expensive high tech game of one-up-man-ship with the thief which you will ultimately lose.

My advice if you use your bike in a high risk area, like a college campus, is to ride a semi-expendable bike and lock it up with a 90% lock. If you can find a place to park it near to a bunch of nicer bikes with average locks, so much the better. Save your good bike for good rides.

jsdavis

Yeah, but that may still mean no bike to ride for a week and then you'd still to find another bike to buy. I think I test rode 5 or 6 bikes before I bought mine. Even after I bought my used Trek 7.5FX, I later decided to go with a Marin Muirwoods 29er instead.

My renter's insurance is only there to protect against (most) monetary loss. Getting home and around is another issue.

SlimRider

Using the right blades with a regular hacksaw and enough time, practically all locks can be compromised!

- Slim

PS.

Angle grinders just speed up the process...

* Quiet as its kept...Bolt-cutters with super long handles can also still be very effective against just about any type of lock, too!

SlimRider

I think you might mean, self-respecting bike thief...will always carry...