Introduction: How to Make a Magic U-Lock

Picture of How to Make a Magic U-Lock

I have a bike, and I had a U-Lock.
I became supremely tired of keeping track of the keys, unlocking the U-lock, finding a suitable sturdy metal bar, and re-locking the u-lock - especially in the winter when the lock was cold and my hands would freeze.
So here's a way to get all the benefits of the appearance of the U-lock, without the hassle.

The idea is similar to this: Homemade U-Lock

Step 1: It's Everywhere, and Free

Picture of It's Everywhere, and Free

If you want a broken U-lock, it will appear.
They drape, discarded, over the high-theft-area bike racks.
They fill dumpsters at your local bike repair shop.

I got 22 of them from my local campus police's bike auction.
They cut off the locks and sell the bikes.
The locks were in a big pile, conveniently cut near the joint, and free.
I walked away with an armload.

After that, all you need is superglue, some magnets, and rocking good tunes.
I like "Ghostwriter" by RJD2.
The Smiths are good, too.

Step 2: Assemble

Picture of Assemble

Glue the magnets in, so they don't touch, but pull the lock closed when they're near enough.

Step 3: Golden Locks!

Picture of Golden Locks!

Now you can hook your bike up to those convenient steel tree-replacements that fill your city.

I feel that if anyone was going to go to the effort to steal one of the bikes I ride, they've already got it. This is just to filter those who see "unchained bike" from those who really want it.

Works well enough.


bleachworthy (author)2007-11-14

yeah, that's totally going to get ripped off. I know people in portland that jiggle every bike lock they see, just to check if it's actually locked. and sadly 1/10 of them are not locked, and he gets himself a new cannondale weekly.

stasterisk (author)bleachworthy2007-11-14

I live in Boston, which isn't as bad as San Francisco, but still has a reasonably high theft rate. My point is that bikes get stolen and all locks suck, and this is a way to make one that at least you can find pleasant to use.

trebuchet03 (author)stasterisk2007-11-14

Bike locks keep honest people honest... If someone has truly decided they want your bike - no bike lock is going to stop them :/

they should make a bike that is it's own lock: the bike splits in two on a hinge, and locks shut. Unlock it, open the bike, slip it over a pole, close the bike, and lock it. If someone wants the bike, they have to cut the bike...rendering it useless

coolo52 (author)Emsaid2012-04-09

hilarious, i love the idea

or cut the pole rendering the pole useless but thats the city's problem

Tommyhzy (author)theadamlevy2009-08-27

Or just detach the brakes. So when they try to ride away... Ouch. (Sorry for the almost 2-year-old post)

vov35 (author)Tommyhzy2011-10-16

**bumps 1 year old post to suggest installing a cam lock in the frame to lock the steering column at a 90 degree angle**

Szech (author)Weissensteinburg2007-11-26

Hey Weissensteinburg, for some ideas, check out the Slingshot bikes, and the Biomega Boston / Puma. Combining the folding of the Slingshot with the lock of the Biomega would be sweet like peanut butter and chocolate. Of course, these days, my bike security involves having a crappy looking old Peugeot that looks like it's falling apart. The only indication that it's a well oiled speeder are the clipless pedals, which are also the only things I'd miss if it were stolen.

true. I knew this guy named hurk up north, if he wanted a bike, he would tear the locks in half with his bare hands, no problem. every one in a while he'd find a tough one he would have to step on, but he always got the bike. the best way to keep your bike secure, is to get boat anchor chain. not the huge huge stuff, but it needs to be pretty big. and attatched to that, needs to be one of THESE locks. hurk could hardly break those, even with a pry-bar.

Evyllity (author)bleachworthy2007-11-15

wtf??? why isn't hurk a fucking supervillain or something?? now that would make a good instructable... how to become a supervillain.

bleachworthy (author)Evyllity2007-11-16

lol, he is a supervillan. he's just going through a phase right now...

That sounds pretty awesome :P Imagine the funny pictures you could take :p

That could be awesome! It would have some pretty beefy hinges, to lock into something useful. Build it and post pictures!

Me build it? Hah!

droo1966 (author)2011-10-16

"Anything one man can code or lock, another can decode or unlock."
Credit to Harry Harrison, The Stainless Steel Rat.

"They steal the nails as well"
Credit to me

db'alexander (author)2011-10-16

If I saw this on a bike I'd think "Ooooh, free magnets" and leave the bike. But that's how I roll.

anasmommy (author)2011-03-03

I like the idea of doing this as a 2nd lock. Makes it appear that your bike is locked with 2 locks but really it is only locked with 1... Then your bike is still locked, but less likely to be messed with as there are 2 locks (or the appearance of 2).

frogmeetcog (author)2010-05-19

These days, it is child's play for someone with a small backpack and no conscience to get through any U-lock, whether it's a Krypto Faggotaboutit or not.... the thief pulls a handcranked carjack out of his pack, puts it between the bars of the lock, and squeeksqueeksqueekCRAAACK your hardened-but-kinda-brittle lock shackle is broken.

I have also heard about thieves putting superglue in the keyholes of beefy locks, so you can't get the key in there, but they can come back at night and do their satanic work on the lock.

Locks only buy you time, tragically. That fake one there buys you 5 seconds, though.

fallenspirit123 (author)2009-09-21

Someone needs to make a bike lock that has the hasp completely hidden, such as the masterlock hidden hasp lock to deter cutting

jlipimpski (author)2009-09-20

RJD2 is so good. I like your idea, i usually never take the time to lock up my bike but do worry about having people see the opportunity and run with it. thanks! i'm also curious as to what those numbers and letters are...

I_am_Canadian (author)2009-04-08

My brothers locked one of those around my neck once. Im never getting near one again.

geekazoid (author)I_am_Canadian2009-05-07

im canadian too

I_am_Canadian (author)geekazoid2009-05-07


zzpza (author)2008-10-26

i know that hex string! lol :D ;) nice idea, but i'd be too scared to use it with my bike. :(

isail (author)zzpza2009-02-25

that is why i have a crappy bike, it will put you in the hospital if youre not careful

PKM (author)2007-11-14

Are those... MAC addresses? Sorry, tangent- it's a nice simple approach to security through deterrence, but by no means infallible, and in my experience there are plenty of budding bike thieves, usually kids rather than pros, who would happily snap a thin chain lock or use bolt cutters on a cheap combo lock but wouldn't know where to start with a good quality D lock. Admittedly if you live in bike-theft-central then it's just increasing the mean time between thefts, but saves on hassle and may let you insure your bike, should you so desire. I became bored with walking a lot faster than I was bored with locking my bike.

mtxe (author)PKM2007-11-14

the code is the AACS encryption key (the one the digg community got so enraged about)

sernatinger (author)mtxe2008-06-28

AACS key for what?

sernatinger (author)2008-06-28

What are this codes?

shepard (author)2008-01-28

Don't forget about the security flaw in old u-locks. The barrel-key (like you see in elevators) can be defeated by purchasing a 25 unlocking tool available at pretty much any store. I won't say what but you can probably ask g()()gle.

leebryuk (author)2008-01-16

Do yourself a favor and just buy a New York Fahgettaboudit U-Lock from Kyptonite. The cost of a trash bike is still more than the cost of the lock. And nothing, nothing sucks more than being in a hurry and finding your bike AWOL. It always amazed me as a bike shop employee on how people would cheap out on the lock. I lived in Northern England where these often served as primary transportation and folks would buy bikes that would be around $300 for shopping, etc. Then they would go for the cheapest set of lights (the halogens that eat a set of c batteries in a couple of hours) and the 20 dollar lock. They'd have no lights within 2 weeks (got tired of buying batteries), a ticket for not having lights, and usually no bike after two months or so. I've traveled in NYC, London, throughout Scotland and I've always used several rules: a) Buy the best lock, pony up the cash, you won't miss it in a week. You'll already have saved the difference in gasoline, and you will have drank the same amount in beer that weekend. b)Park in a conspicuous space, but don't expect that to do crap for you. And yes, they will cut through trees to get to your bike. All they have to do is basically push and break the trunk of that sapling in the park. c) Call the cops if you see someone stealing a bike. Cops love stopping them, because they usually have an arrest warrant as well as drug paraphernalia on the thief. And someone should kick that guy in the balls for stealing bikes. I hate that with a purple passion.

fungus amungus (author)2007-11-14

Finding a new bike is a much bigger hassle.

shooby (author)2007-11-14

I think it's a good idea. Of course, proper judgment ultimately determines how effective it is, i.e. where you lock it up, when, etc. Someone out bike hunting at 4:00 in the morning will have the time and the privacy to investigate bikes that are locked better. People who steal bikes during the day, in busy areas, will not even bother with a bike that looks secure. Especially if it's a rammel-kast (beater, in Dutch). More bikes are stolen each year in Amsterdam than the number of people that live there. I didn't do it!

razordu30 (author)2007-11-14

Interesting, but I wouldn't bother doing this unless you have a cheap bike to begin with. If you have a decent bike, get a decent lock. I hate carrying keys, too, so I got one that uses a 4-digit combination that you can set. Best of both worlds!

Lftndbt (author)2007-11-14

Nice work!

aneel (author)2007-11-13

Heh. Nice background. I'm surprised that 21 hasn't been repainted yet.

xsmurf (author)2007-11-13

I like the idea.... I lived in Japan ;) We have one of the highest bike theft rate in the country here, so I'm not sure I'd rely on this. I don't even trust my U lock. But hey the instructable was nice and funny :) Ghostwriter is a kick ass tune!

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