seeing as the d shape is thick hard steel, and i would guess hardish to cut, how do thieves break them open mainly?
i would have thought they were very hard to break and therefore the lock of choice?

Not hard to cut IME, but the locking mechanism is almost always the weak spot in any lock.

I'm not sure discussing how to break 'd' locks is a good topic on here tbh.

cycle D'locks are best for carryign around and using.

For ultimate security some of the chain based solutions or motorbike d-locks are probably tougher but too heavy to carry far…

i heard the early types could be opened by jamming a biro inner into the joint between the shackle and the bar and releasing a sprung loaded lock thingy. (like jamming a credit card into a yale lock)

mine is more like a dead lock, so i would imagine is a bit of a sod to break into.

depends on the lock design?

Back in the day (90s!) you could buy a product called Billy's Bones or somesuch. These were flat steel bars with a loop at each end which you slid onto your D lock. The idea was, it would stop folk using a car jack to bend the sides of the lock out, popping it open.

Someone tried the car jack thing on my £9.99 no-brand D lock a few years ago, but it held out!

As Ck says probably not hard to cut if you have the right tools. They can also be broken using a bottle jack to bend the "U" of the lock outwards with the point where the little elbow pops out:

http://www.youtube.com/watch?v=eoqNC7aUeXI

(People who aren't fans of death metal may wish to hit the mute button)

There are also shedloads of videos of people opening locks with the old-style circular barrel with pens, viz:

D-locks will mainly spring open with a hydraulic jack (just requires; bravery, persistance and a blanket to stop the bits flying off into you when it shatters/brakes appart)

Chains will sucumb to bolt croppers.

The only safe way to lock a bike out and about is a combination of the two. But that's impractical. So I just use the old 6speed tourer which is invisible to thieves despite probably being worth more than my cheepest MTB.

On all day rides either keep it in sight at all times (no it wont be safe when you just pop into Edale/Ambleside/Cannock post office for 10 seconds to buy some mint cake). Or buy one of those lightweight locks that's combined with an alarm, or a small cable lock that'd take 5 seconds to cut, but hopefully long enough to discourage the casual thief.

Can you actually get a hydraulic jack into most modern D-locks? I note that newer ones seem to be quite a bit narrower and shorter, even assuming you don't get one of those ultra-short ones that fakengers tuck into their belt loops.

I was always told the main thing with D-locks is to try and get as much stuff as possible into the D. If you buy a big (long) D lock and don't fill it with frame/wheels/railings etc. then a thief can put a long lever in and bend the lock off – similar to the bottle jack thing I suppose.

The only time I had a bike nicked, it was from a uni bike shed with a really feeble lock on the door. Some scrotes broke the lock on the door and once they were in, there was plenty of space/privacy to remove all the locks from all the bikes in there and nick the lot. I think they got away with 8 bikes. My D-lock (cheap halfords lock on cheap halfords bike) was cut clean in two.

I have been looking recently on a site called something like torc-anchors for some additional security.

id heard of the bottle jck thing, but thought it would just jamm the lock even tighter…apparently not. this must only be on cheapo ones tho…?

lots of locks say about being drill proof, does anyone even try this as ive never seen any that people have attempted it on?

A more expensive lock will be harder to break in general.

another thing to look for is the locking mechanism – does it lock both ends of the shackle or only one end with teh other being held by a peg or cutout in the leg of the shackle – double locking ones are much stronger.

Cryospray and a couple of good whacks with a cold chisel beats any lock in about 20 seconds, simples innit…….

Cryospray, if you happen to carry some around. Not that easy to get and quite expensive way of getting a bike. Most bike thieves are lazy and greedy by their nature therefore anything to make them work harder is better.

Though I have seen plenty of posts about people losing keys and using a grinder to break the lock and never being challenged despite the time/noise involved.

In general the more you pay, the safer it will be. Often higher end locks come insured it it does fail.

Cordless angle grinders are pretty cheap.

Lidl were selling 36" bolt croppers a while back.

Scrotes will cut an your favourite frame to get it free to strip the parts.

Good point about cutting the frame, someone with enough knowledge of the bike market (ie that its better value to strip and sell the parts than the bike) won't bother tackling the lock, just cut through the coke can thin frame tubes instead. So an opportunist looking for something to flog in the pub for smack money would probably attack the lock, bike thieves who know how to fence the goods would attack the frame.

But for the lock itself filling the lock as much as you can and making the lock as inaccessible as you can are the two tricks- if its a time-consuming fiddle to get at the lock and open it with a key then you are adding discouragement to anyone trying to break it. Two different modes of locking are another trick. If me and the GF are riding together i carry one type of lock and she carries another. But if I'm riding a decent bike I do just that, I ride it. I don't leave it places, that what cheap bike are for.

<<But if I'm riding a decent bike I do just that, I ride it. I don't leave it places, that what cheap bike are for. >>

also a good reason to a use a brompton – you can just take them into shops/work

so has no one heard of drilling being done?The lock on one of my double glazed window handles had the key lost when it was locked.i tried drilling the tumbler out and it gave way in seconds!then put a screwdriver in the remains and twisted to make it work.

To echo wwaswas, why exactly are we talking about how to break into locks on a biking forum.

People just interested in the topic of conversation……….or more likely looking for tips. ❗

I think the 'drill proof' ones have a wee ballbearing in the centre (of the type you open with those funny circular keys / bic biro) that makes the drill difficult to aim down the centre of the barrel.

I think in general thieves favour speed and quiet, so something a bit quieter, quicker and more brutal than a drill or a cordless anglegrinder would be favoured. A big metal bar for instance.

why exactly are we talking about how to break into locks on a biking forum

The info is out there already – just have a look at how many Youtube vids there are of people breaking locks. Doing the internet equivalent of sticking your fingers in your ears and singing loudly won't make a blind bit of difference to that.

The best thing to do is recognise the limitations of your equipment and either get stronger locks, or come up with strategies that prevent the most common methods of theft from being used.

Good point, lets add to the already huge resource on the internet of how to nick bikes. How short sighted of me!

Having just had my bike nicked at the weekend, and knowing there are 2no. different types of lock still attached to the bike frame as the miscreant cut through the steel box section frame it was locked to.

I just felt this seemed odd to be discussing such a topic from an original post not a million miles from where I live!

You have to forgive me for being a bit precious at the moment. 😳

It doesnt matter how cheap angle grinders are, or long handled bolt croppers. If they're gonna nick your bike, chances are they've hit a shed the previous night and nicked the tools.

Been in the lock business some time, and the simple fact is what can be made by man can be unmade by man. Its that simple. The deal is that crooks follow the line of least resistance, so you are trying to make that line lead to someone elses stuff.

That apart just remember to think like a crook. they will go for whatever is easiest, and they will not worry about consequential damage when they do that, so or example if the wall to your house is the easist route for them to follow, and its worth the hastle then they will go through it.