1

I have a new bike, not very expensive... but still doesnt want it to disappear the next day and I was looking at different locks and came across lock that have an alarm which triggers a siren. Not sure how good they are. Would anyone recommend ?

Weiwen Ng
  • 31,327
  • 3
  • 50
  • 113
MashmanBM12
  • 11
  • 1
  • 2
    I think a strong U-Lock (Abus, Kryptonite) is still your best bet. Make sure you use it correctly (e.g. don’t just lock the front wheel to something). – Michael Dec 10 '21 at 10:49
  • 1
    Note that in our FAQ, we do say that we consider product recommendations off topic. – Weiwen Ng Dec 10 '21 at 13:24
  • thank you very much – MashmanBM12 Dec 10 '21 at 14:37
  • 1
    WHOOO- BAM! Twaaaang! crunch! What alarm? – Andrew Henle Dec 10 '21 at 15:08
  • @Michael And a separate cable lock helps a lot - not a chain. A cable requires a different set of tools to defeat than a U-lock. Both a U-lock and a chain can be cut rather quickly with a good grinder. – Andrew Henle Dec 10 '21 at 15:13
  • @AndrewHenle: Pretty much all cable locks are rather weak because the cable consists of small individual strands which can be cut one-by-one, sometimes even with a pair of strong wire cutters. The nice thing about cable locks is that they are long and flexible, so you can use one in addition to a U-Lock (which secures the frame + possibly rear wheel) to secure the front wheel or sometimes saddle or luggage. – Michael Dec 10 '21 at 15:27
  • 1
    @Michael The point was a cable lock requires different tools to defeat than a U-lock, whereas a chain can be defeated with the same tools as a U-lock. And a good cable isn't that easy to unravel... – Andrew Henle Dec 10 '21 at 16:00
  • @AndrewHenle: What tools work on a U-Lock but not on cable locks? A bolt cutter or angle grinder works perfectly fine against a cable lock. If the braided cable is difficult to cut (because it vibrates, is difficult to keep in place etc.) you can just cut at the lock body or even through the lock body itself. – Michael Dec 10 '21 at 16:04
  • @Michael Try holding a small lock body in place with one hand while cutting it with an angle grinder. Make sure to count your fingers afterwards. – Andrew Henle Dec 10 '21 at 16:17
  • @AndrewHenle: I did it once with an old cable lock I found in the basement (without key), just to see how easy it would be to cut. Turns out it is easy. The biggest problem with holding it in your bare hands is actually heat. But in any case, a well equipped thief with an angle grinder would probably also have some pliers to hold the lock (or would simply also bring a small bolt cutter). – Michael Dec 10 '21 at 16:21
  • @Michael A well-equipped thief isn't likely to target anything but expensive, high-end bicycles. But an opportunistic thief with just a half-decent battery-powered grinder can defeat U-locks pretty quickly. Again, you missed my entire point: you make it so the thief has to be a well-equipped professional to get your bike. And if your bike isn't one that a well-equipped pro would target in the first place... – Andrew Henle Dec 10 '21 at 16:25
  • In my opinion if you have the frame secured with a strong U-Lock you gain very very little by also using a cable lock in addition (also just through the frame). It only adds hassle every time you have to lock and unlock it. – Michael Dec 10 '21 at 16:29
  • 1
    Comments are for clarification of the question, not extended discussion. – mattnz Dec 10 '21 at 21:18
  • 1
    Does this answer your question? Best type of bike lock (materials, style, etc.) – mattnz Dec 10 '21 at 21:18
  • @AndrewHenle I am, or rather was, inclined to agree with you, but I've seen the results of both angle grinders (risky, but not enough to put off a thief) and bolt cutters going through cable locks (yes the blade is the wrong shape, but with enough leverage that doesn't matter). Where I do agree is that an additional cable should be a lock in its own right, as this adds a time factor that a chain or loop-end cable doesn't. – Chris H Dec 13 '21 at 15:17

3 Answers3

2

I'm leaving all the general anti-theft advice aside and try to focus on the alarm side.

Basically I believe there are two different types. One with some loud audible system on the lock/bike itself, and another type that sends an alarm to your phone to alert you about something dodgy.

The first type (audible alarm) is not likely to help much. A good lock has to be cut with power tools, so this makes a lot of noise already. If that noise doesn't alert people, then the alarm won't make a difference. And once the lock is cut, the thief leaves the lock with the alarm behind and escapes with the bike, so from that point onwards the alarm is pointless. It would perhaps make more sense if the alarm was separate from the lock and is fixed to the bike, as a rider with a howling bike might attract some attention or get worried and dump the bike after a few metres, so you can recover it. But I don't think any of the locks work that way.

It can be potentially useful if you are still nearby (eg. in a cafe or a shop or at home) and can get to the bike within a few minutes when you hear the alarm and actually stop the thief. But in a noisy environment you may not hear it if you're inside.

Here the other type, that sends an alarm to your phone, is potentially more useful. Also with this alarm the thief will not know that you have been alerted.

Some of these systems include a GPS tracker so you can find out where the bike is when you arrive too late. This seems more useful. I installed a GPS tracker once, but in the end the hassle of keeping it charged and arming/disarming it was too much, so I removed it in the end.

Also, what triggers the alarm? I think it's usually movement, but bikes can be moved inadvertently for many reasons, as people bump against them. So you'll likely get more false alarms than real alarms. Even car alarms go off a lot although cars are much bigger and people don't touch them.

Finally, some alarms (especially the phone alert and/or GPS trackers) are expensive (and you may need a subscription to use them), so you have to weigh the risks. If the risk in your area is such that a bike with a good lock has a chance of getting stolen once in five years, but you buy a new one every five years anyway, then it's not really worth spending additional money for alarms beyond a good lock. If you are in a really high risk area with an expensive bike, then a GPS tracker might be a good idea.

I had my bike stolen from my garden shed 3 years ago, and an alarm might have woken me up, but being more careful with locking the shed (which I had forgotten to do on that particular day) would've helped even more. But in the end I was almost happy about the theft as it made me buy a new bike, which I had started thinking about anyway as the old one wasn't so great anymore.

An update on the Trackers - thanks to comment from @200_success: A new alternative is the Apple AirTag or the Samsung SmartTag (possibly similar systems from other companies exist). These are small tags with Low Energy Bluetooth technology that the smartphone can locate. As they are small and the battery (CR2032, ubiquitous battery in various items like fitness trackes or kitchen scales) is supposed to last for a year, you can hide one (or several) on your bike somewhere.

If the tag is not within reach of your own phone, then it uses the network of other Apple/Samsung users to locate it. It seems (see e.g. this Test (in German)) that it takes only a few minutes to locate a tag when it is in a reasonably busy place (they left their tag in a car that had an accident and were able to locate it in the workshop and the paintshop). This seems a promising way to locate a stolen bike.

Stephan Matthiesen
  • 2,252
  • 11
  • 15
  • An alternative to GPS trackers these days is an Apple AirTag. It won't phone home as reliably as a GPS tracker, but it's cheaper and uses less battery. You could hide one or two of them on your bike in plain sight by using some clever mounts. – 200_success Dec 13 '21 at 09:30
  • @200_success Thanks, I didn't know (even though I'm a fairly technical person), this is indeed useful and I added a paragraph. – Stephan Matthiesen Dec 13 '21 at 10:52
0

Sirens are utterly useless - consider how many people ignore a car or property alarm.

They simply can't be loud enough to be a deterrent on a bike and remain small. Also they need battery, will be flat the one time they're needed, and can be defeated by yanking a wire, smashing the speaker, or simply muffling it with a hand or cloth.

  1. Your best option is to bring the bike inside, such that it doesn't need to be locked.
  2. The second best is to lock it outside in a place it cannot be seen.
  3. Locking it in sight of casual passers-by requires a decent lock, removing all easily-stolen items (lights, water bottles, tools) and to secure the saddle and wheels. Ideally you'd have two locks and secure all of it to something immovable.
Criggie
  • 124,066
  • 14
  • 180
  • 423
  • 1
    From my gut feeling I agree that audible alarms are mostly useless and everyone just ignores them. But are there any statistics on the matter? A properly designed one should use none or very little battery and should be hard to muffle or destroy. – Michael Dec 11 '21 at 13:34
0

Your approach of loud sound is not feasible.

The typical way locks are broken are very loud. One foolproof way for the thief is to carry an electric battery-powered angle grinder. It will make a very loud sound when operated.

Another way is to carry a ramset gun. This may not be easily available on all continents, but at least in United States where everyone can buy an assault rifle from a supermarket, firearms that are intended to drive nails into concrete are readily available and will easily break most locks. As a firearm, it is very loud too. Someone will think the bicycle thief committed a murder!

Since most common ways to steal bikes make a loud sound, why do you think a second different loud sound would benefit you in any manner?

About the only way that is not loud, but is somewhat slower, is to use a hydraulic jack. This can be made harder by using the smallest U-lock that you can buy and lock the bike in such a manner that the "U" of the U-lock is as full of stuff such as bike tubes or tires as possible, so the thief can't fit a hydraulic jack here.

Picking a lock is obviously possible. On door locks, there are locks available that are so hard to pick that even LockPickingLawyer on YouTube can't pick them (newest Abloy locks), but on bike locks the best locks available are disc detainer cores with no special anti-pick features, such as the Kryptonite Evolution U-locks. Nevertheless, even these Kryptonite locks require special tools (a disc detainer pick) and special skills to use the said tools.

If you want to prevent a thief cutting or breaking your lock with a hydraulic jack, buy a Skunklock. It contains a chemical inside the lock that will evaporate when being destructively opened, and is so annoying the thief will probably run away after encountering the chemical. Even Skunklock won't prevent lockpicking, though.

juhist
  • 18,668
  • 3
  • 27
  • 49