maximusvt

So I'm aware that if anyone really wants my bike, they'll be able to break through whatever I have it locked up with if they have the right tools... Currently I just use a combo cable lock, which is plenty for where I live (almost overkill really). I was thinking of getting a U-lock for city riding, and using both locks together. It looks like the combo u-locks are generally cheaper than the keyed ones, is this because they're less secure?

ignominious

Combo locks are essentially worthless outside of crime free areas.

Basically they require no force and no skill whatsoever to break. When I was a kid we used to have challenges to see how quick you could run through combinations sequentially to crack a lock in the bike shop. The quickest on a 4 ring, 9 digit combo lock was something like six and a half minutes. It really is just a matter of time before someone steals your bike.

Buy a good D Lock or Chain Lock, bare minimum of Sold Secure rating Bronze (although it's more than worth the little extra money required for a Silver or Gold) and accept the fact that carrying a key isn't that much of an onus for riding your bike for many long years.

Of course if you do continue to carry a combo lock and forget the number, rest happy in the knowledge that it won't take you that long to stel your own bike and you get to keep the "lock" afterwards.

recursive

Emphatically yes. I can open combo locks in a couple of minutes. I've had no training and don't know how to pick 'real' locks. They are dead easy.

Michigander

I know a guy who can crack combo locks, but to me its just a silly hobby. A hammer works a lot faster. On the other hand, a hammer will have a much harder time breaking a keyed lock.

tbdean

How does this work? Just spin the dials while applying force to open it? It really only takes 6 minutes to go through all the combinations?

Or do you have to try 0000, check, 0001, check, etc.

ignominious

It really only took about six minutes to go through enough combinations to open a lock. Fast hands, a light touch and some practice is all it takes. Rules apply that even a 6yo can learn, such as ignore three or four numbers in a row, that speed up the process. Also, combos rarely begin with the numbers 1, 2 or 3 which saves you 4000 combinations alone.

Imagine at most ten minutes work for maybe $100 for your $500 bike. That's basically $17p/h, which is above the average earnings in the US. Fancy a career change?

donnamb 

If you are doing the double lock thing with a cable and a good U-lock, some manufacturers will key both locks the same if you buy them directly.

TomatoSue

So does anyone know why they still sell combo locks if they are so easy to open? I feel very stupid cos I've got one, even bought it at the LBS... perhaps they're counting on me buying another bike from them when this one gets nicked!

tsl

Why does McDonalds sell food shown to be unhealthy? Why do car manufacturers sell cars with less than a five-star crash-test rating? Why do real estate agents sell homes on flood plains?

It's all the same really. People's needs are different, and so are their desires. It baffles me as to why someone would pass up "good" for "cheap", but discount stores make a killing at it.

maximusvt

Well like I said, in my town even an easy to crack combo lock is overkill. I mean I'm careful about where I lock up and everything but most people don't worry about leaving their bike around outside, unlocked for half an hour or so anyway. And if there's another bike nearby that's less locked up than mine, I don't really worry about what I've locked mine up with.
Of course, now I'm gonna have to cough up more for something with real locking power...

Banzai

However...

A lock is more deterrent than anything else. Could a thief crack your combo lock? Yes (though I don't see one having the patience to sit there and cycle 4000 combos). Can a thief break any lock? Yes again.

If you lived in a high crime area with very determined and talented bike thieves, you would be right to worry about your cheap combo lock if parked on a bike rack next to a bunch of bikes that are double locked with some pretty tough equipment.

Locks are more about making you a difficult target, rather than vouchsafeing absolute security. A thief will typically take the easiest target first, unless you have a bike that is simply impossible to pass up. (Most thieves don't know this though.) Your one lock vs another guy's no locks makes you the more time consuming and difficult target. Your two locks (even if they are both combo locks) vs another guy's one lock again makes you the more time consuming target...especially if they are mixed chain and u-locks, since each takes a different tool to cut.

And perhaps you'll get a super thief who happens to be both a speedy human random number generator and a man with feather light dexterity in his fingers. This same thief has a passion for combo locks typically only reserved for Rubik's cubes, and he salivates with anticipation when he sees your bike locked up in such a tempting manner.

Somehow, I doubt it.

I'd say just get the combo lock, if that's what you want. It's one more obstacle in the way of walking off with your bike, and that should be good enough, particularly given what you said about crime rates.

But, if you'll spend all your time worrying about it...then get a lock or two that will give you peace of mind.

alanbikehouston

Most combo locks use low quality shackles. They can be opened in five seconds by a crook with the "right" $10 tool.

If you live in "Friendly Village" and own a $100 bike, any lock will do. If you live in a major city or on a college campus, and leave your bike out in public view for hours at a time, you need a serious lock. Get a "gold" rated lock listed by the British testing agency at:

www.soldsecure.com/Leisure.htm

donnamb 

Because there's a sucker born every minute? There are places that even a combo lock is overkill, I just don't go to those places on my bike.

geo8rge

I use a krytonite combo lock in NYC. The problem I had is that people were hitting the latch with a hammer jamming it. I had to cut through 2 of them (replaced free by kryptonite), cutting with Ti blade hack saw was not that hard. I now use a cable + combo. I have not had the problem again.

As to cycling throught all combos. 4 digits is 10,000 combos. 1 combo / second 10000/(60*60) is 2.8 hrs.