I already have the cable cable kind with the combination lock. It just seems cheap and easy to break into. Is that sufficient or are the U shaped ones better?

  • 1
    Cable locks are easily snipped with bolt cutters. U-locks definitely better.
    – user313
    Commented Mar 9, 2011 at 23:15
  • 2
    @wdypdx22: bolt cutters are the wrong tool - often you end up with too many loose strands that are not cut because the jaws don't completely close. Standard pilers or side cutters work, but sometimes slowly. A dedicated cable cutter is only $20 or so and will snip the cable as quickly as you can squeeze the handles. The advantage of side cutters is that they also work on cheap chain-and-combination locks. Should you, for example, have a rack of abandoned bikes you need to get rid of.
    – Мסž
    Commented Mar 9, 2011 at 23:20
  • I wasn't providing a tool recommendation. Thieves don't care whether it's the right tool or not. A group of bike thieves was recently busted around here and one of their tools listed was bolt cutters.
    – user313
    Commented Mar 9, 2011 at 23:31
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    Welcome to Stack Exchange! While shopping recommendation questions aren't prohibited on this site, you might consider rewriting this to ask what kind of lock is more likely to meet your needs. Also see this post on the Stack Exchange blog for more information on this. Again, welcome to the site, and thanks for asking. Commented Mar 9, 2011 at 23:49
  • 1
    Here is a funny tube youtube.com/watch?v=pTPFrww6zdA Commented Mar 11, 2011 at 11:29

5 Answers 5


Honestly, I must say that there is no such thing. Sometimes you can find a U-lock used on Craigslist or similar websites and you might get a better deal. Otherwise, $30 is below bottom-of-the-ladder for U-locks.

And think about it. What are you paying for with that 30-50-even $90? It's a one-installment insurance policy on your bicycle. I would suggest that you lay down some real money and get a good lock. If you don't, you can either

  • Never take your bike anywhere that won't allow you to bring it inside with you.
  • Plan on replacing your bike frequently and encouraging the bike thieves.

My frivolous answer: Really. Maybe you shouldn't spend a bunch of money on a bike lock. If you get a cheap lock, the bike thieves will have no reason to learn how to open the more expensive type which will leave my bicycle all the safer!

Bike locks cost real dough because they are designed to stand up to real abuse.

I once had a job where I routinely went around a park with a pair of huge bolt cutters, removing the bike locks (and sometimes bikes) that were abandoned there. The cheap locks are a hellva lot easier to cut off of railings than the beefy OnGuard types.

You do get what you pay for, here, at least in the range of $0-50. Cheap locks are almost not worth buying. A $50 U-lock will stand up to several tries with a pair of bolt cutters that have three-foot levers attached to the handles.

  • The "designed to stand up to real abuse" thing is kind of suspect to me. Kryptonite locks were at one time vulnerable to the "bic pen" problem. So they changed the key type. Seems to me that any lock could be easily opened by a person with the proper lock picking skills. I mean, the bic pen just happened to be the right size, but it was really just a universal blank key. Are there universal keys that happen to fit the newer types of locks as well?
    – Kibbee
    Commented Aug 11, 2011 at 16:35
  • I'd be wary of buying a used lock on craigslist - all someone needs is the little key tag number from kryptonite to make a spare key and steal your bike.
    – Batman
    Commented Oct 14, 2014 at 13:10

I watched Youtube videos of people breaking various locks:

  • Cable - using manual clippers that you can easily carry inside a jacket: snip the cable in one snip
  • Heavy chain (e.g. as used for locking mopeds) - using cutters with 5-foot-long handles: much hopping and heaving with whole body weight, takes about 20 seconds
  • U-lock - using an angle grinder (a kind of power tool, perhaps with diamond cutting surface): takes 5 seconds, and a power source (I don't know if you can get battery-operated ones)

Summary: a cable will [only] stop 'casual' thieves who don't carry a tool with them; and would be no deterrent to a regular/professional thief.

  • David Brower stated once that legislating for "Wilderness" just set wild places aside until the next battle with the developers... whereas developing land into a parking lot transformed it forever. Putting a lock on your bike protects is from theives for now--any lock can be broken. Once it's stolen, though, it's usually gone for good. It's a pain in the ass to walk around a public place with a three-foot-long pair of bolt cutters and a bicycle--most thieves will avoid doing this in broad daylight! (Not to mention walking around with a generator, an angle grinder, and a bicycle!)
    – DC_CARR
    Commented Mar 10, 2011 at 19:28
  • Note that high-quality (about $50+) U-locks are made from hardened steel. While these can still be cut using an angle grinder, it can take a minute or more, and will create an enormous amount of sparks and noise, plus you'll likely ruin the grinder's blade in the process. So it's not really an option for most thieves...
    – sleske
    Commented Mar 11, 2011 at 7:57
  • And BTW, yes, there are battery-powered angle grinders. HOwever, they're typically not as powerful as the ones that run on mains power, so cutting will take even longer.
    – sleske
    Commented Mar 11, 2011 at 8:00
  • A 4" cutting wheel for a small angle grinder is only about two and a half bucks. This cost is probably not on a thief's mind if he's gone to the trouble to come hunting bicycles with a grinder. If the situation is such that the noise and sparks created by a grinder are acceptable to a theif, he might as well use a gasoline-powered cut-off machine... stihlusa.com/construction/cutquik.html Plenty of power there to cut through any lock. As I said... any lock can be broken, the tool exists.
    – DC_CARR
    Commented Mar 14, 2011 at 19:22
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    @DC_CARR My LBS said (while selling me a lock) that it isn't that a lock cannot be cut: it's that when it has a good lock, sufficiently better than its neighbours' locks, your bike is no longer one of the easiest of all the available targets.
    – ChrisW
    Commented Mar 15, 2011 at 1:18

You're much better off with a D lock (U lock) because they're harder to remove without the key. A cable lock can be cut through with a cheap tool that's easily carried in a pocket. Cheap D locks are pretty similar to each other, but avoid the cylindrical key types (if you can still find them) because instructions on how to pick those quickly are all over the internet.

The comment below about smaller locks being more secure is correct, but with the proviso "if used correctly". A smaller lock is often harder to use correctly. The larger locks make it easy to lock the rear wheel + frame to a poorly located pole or fence, so are often more secure in a specific situation because they can lock your bike correctly where a smaller lock cannot. I use a small D lock (ABUS Granit) but have locking QR skewers (pitlocks) so don't need to lock my wheels separately.

Without knowing your location a specific recommendation is not possible - I would use my LBS but if you're not in Melbourne they might not be the best choice. I used google and found this online site which seems to have a reasonable selection.

  • Note also that for otherwise comparable U-locks (same locking mechanism, same thickness of steel), the one with the smaller opening will be more secure.
    – freiheit
    Commented Mar 9, 2011 at 23:30
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    @freiheit - but also harder to use, because there's less of it. Updating my answer...
    – Мסž
    Commented Mar 9, 2011 at 23:38
  • even with locking QRL skewers, do you use cables like [1] or with two-open ends? I have seen a lot of open-ended cables in use with touring bikes and just a cheap rear-wheel-lock to which it is attached to lock the wheels. Since I don't have a locking QRL skewers, would a product like [1] be enough to lock the wheels during touring? What do you think? [1] bikelockshops.com/ML8156DPS.html
    – user652
    Commented Mar 10, 2011 at 0:58
  • 1
    @hhh: I'd buy locking skewers over a cable if I had the choice. For my velomobile I use a double ended cable and loop it through itself at one end (around a pole) then thread it through the bike and lock it to a wheel (the velomobile has no lockable frame)
    – Мסž
    Commented Mar 10, 2011 at 1:27
  • I have pinhead security skewers (and headset, saddle post), and use a D-lock through 1 wheel and frame, with an independent cable lock through the other wheel, helmet (usually, depends where) and frame. No extra weight compared to an eyelet cable, and more versatile (a D-lock won't go round a lamp post if stopping outside a shop). Round here, there are so many cable locks that the mere sight of a D-lock was a good deterrent when tested, so from that point of view, a cheap one has benefit.
    – Chris H
    Commented Jul 30, 2013 at 12:44

Smaller locks are harder to break than big locks - if you know there is a rack that is thin enough to lock the frame to.

Having a cable/chain as well gives you more options - a chain is harder to snip.

enter image description here This is about $30

Two locks are always better than one - even if it just causes the thief to look at the next bike.


I saw a demonstration where they compared U/D-locks and cable-locks.

None resisted the cable cutter, but the thicker the lock was, independent from the type of lock, the bigger the cable cutter had to be.

Conclusion: Use a very thick lock. Don't look at the type.

  • Although it's true that difficulty depends on thickness, I think it would be misleading to say that it's independent of type (e.g. that two different types of the same thickness have the same difficulty): I think that a cable, made of several strands, which flexes, is easier to cut than a solid bar or U-bolt; because you can cut one strand at a time; and because it flexes it's easier to apply a shear stress.
    – ChrisW
    Commented Mar 10, 2011 at 3:10
  • They needed a few seconds for both types. I know what I saw, but of course, thefts with bad tools might be stopped. However: Most of the money you spend for the name. Commented Mar 10, 2011 at 4:22
  • I've cut through all sorts of locks. Given the choice and with limited time, I'd rather cut a good-quality cable than a good-quality U-lock. Just the same, given the choice between a totally chintzy U-lock and the beefiest cable on the market... I might take a crack at the chintzy U-lock. So. I agree with you to a certain degree. Chintzy U-locks are made of poorer quality steel that will snap quickly whereas thick cables require a bit of time to "chew" through. I still recommend a good-quality U-lock over all cables, though.
    – DC_CARR
    Commented Mar 10, 2011 at 19:23
  • A high quality U-lock made from hardened steel is practically impossible to cut with a bolt cutter. You'd need an angle grinder.
    – sleske
    Commented Mar 11, 2011 at 7:59
  • The better Kryptonite locks were a little easier to cut through with a bolt cutter than the better OnGuard ones... but I have cut through both. Note that my bolt cutters had four-foot handles.
    – DC_CARR
    Commented Mar 14, 2011 at 19:29

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