How to Make a Magic U-Lock




About: Hi! I'm Star Simpson! I'm a real me! See more at []. photo by [ Jeff Lieberman] ( stasterisk - my name is Star, and when I was 13 I ...

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

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

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

Step 3: 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.



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    39 Discussions


    11 years ago on Introduction

    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.

    13 replies

    Reply 11 years ago on Introduction

    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.


    Reply 11 years ago on Introduction

    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


    Reply 11 years ago on Introduction

    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.


    Reply 11 years ago on Introduction

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

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


    7 years ago on Introduction

    "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


    7 years ago on Introduction

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


    7 years ago on Introduction

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


    7 years ago on Introduction

    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).


    8 years ago on Introduction

    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.

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