Modified Bike Lock (aka Uber, Epic, Mega Lock!)




About: Did you know that sewing needles are sharp, and that hot glue from a glue gun really is hot? ouch! I never learn. i should be an honorary spokeswoman for Band-Aid brand first aid products considering the ...

Yup, I just had a couple bikes stolen from me.  So you bet your buns I am not only incredibly angry at the person who hopped my fence and stole my bikes, i am super paranoid now too.  We are in full crisis lockdown mode at Chez much so, you would have thought someone came and rooted through MY fridge and sat around and watched MY new episodes of Real Housewives on MY Tivo.  But hey, my whole thing is that it never hurts to be extra cautious.  Within a matter of hours after the theft took place, I put in an alarm system in my house and motion sensor lights on my patio and brought all our bikes inside the house.  But keeping our living room stocked full of bikes this isn't exactly a long term solution.  I need to be able to keep all of my bikes (and my boyfriend's bikes) outside, and feel comfortable in the fact that the next piece of scum who hops into my yard will be super moded that they can't take any of my goods. Having 4 U-Locks with 8 keys (because they come in pairs) just wasn't the solution for me either.  And 4 locks?  that can get expensive! 

Thankfully with a little creativity, some fancy welding work, and a pretty good sense of humor, the modified, uber, epic, mega lock was born!

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Step 1: Things You're Gonna Need

  • U Lock (we used an Onguard Bulldog 5006 Pitbulll Mini Series Lock- retailed $45)
  • MIG Welder**
  • Cut Off Wheel
  • Angle Grinder (24 grit grinding disc)
  • Two metal rods cut to desired length.  We used hardened steel at 40" in length; long enough to lock up 4 bikes.   (be sure that the diameter of the rods are the same or close to that of the original lock)
  • Vice Grips
  • Plastic accordion tubing
  • Spray Paint

**If you don't own a MIG Welder (gasp!) and live in the SF Bay Area, near Detroit, MI, or Raleigh, NC, don't fret.  You can use the welder at the Tech Shop!  ***

Step 2: Cutting the Lock

To get started, you want to make sure that you take good measurements of where you will be cutting and welding.  You know the saying, "measure three times, cut once!"

Remove bottom piece (the lock) so that you are working on the original U rod of the lock, and take off any protective rubber that might be on it.  

On each side, make a cut just above the locking ends of the rod, and just below the curve of the top of the rod, basically somewhere in the middle

Measure at equal points and mark where you will cut.

Using a cutting wheel, cut through the markings on the rod.   Originally I tried using a band saw, but it wouldn't cut because the rods were made of hardened steel, which means it resists traditional cutting.

Step 3: Grind Off Edges

Using the angle grinder with a coarse grit disc, grind the edges to a point at roughly 45 degree angle.  Grinding at an angle ensures proper weld penetration when you weld the pieces together.

Grind all ends of rods that will be welded (original and new steel) 

Before welding, use a straight edge (in this case, we used a piece of angle iron as seen in the photo) to make sure the parts to be welded are properly aligned.

Step 4: Weld Baby, WELD! (the Top Edition)

Now, as exciting as it may be to start welding like a crazy pyro, it is important to be sure that you don't just weld each piece all willy nilly, otherwise, you are going to end up with one giant piece of wonky metal, and a really ruined Sunday.  The next two steps will help ensure that you don't eff it up, and have a perfectly level, and perfect fitting lock.

FIRST WELD:  Once you have aligned the long rod to the original curved end (with the help of a straight edge), tack weld the two pieces together, so that when you go to make the final welds, the pieces won't move or shift. 

SECOND WELD: Line up the long rod as you did with the first rod that you just welded.  Measure the two floating ends BEFORE you tack to be sure that they are are the same distance apart as they are at the top.  Essentially, you are making sure before you weld, the two long pieces are not bowed in or out.  Keep it symmetrical baby!

Step 5: Weld Baby, WELD! (The Locking Bits Edition)

Before you weld the final two ends together, you wanna make sure that you have the locking ends correctly oriented so that you can actually use the lock. Imagine welding it all together and then it not fitting!  FAIL

Lock each machined end (the stock ends of that you originally cut off) into the lock and lock them in place with the key.  This ensures that when you weld the giant rod use to the machined ends, everything will be aligned.

Holding the base in place with vice grips, tack weld the long U rod to the machined ends (still attached to the lock base)

Once tacked, remove the lock (and for good measure, re-lock to make sure the locking mechanism still functions before you weld).
If all is good, remove the locking base (so the heat doesn't destroy it) and finish welding.

Step 6: Finishing Up the Metal Work

Once you have welded it all together, grind down your welds to a smooth finish, and spray paint to prevent the bare metal from rusting

Now step back, light up a cigar, because you just created an uber, epic, mega lock! 

Step 7: Finishing Touches- Protect Your Investments

Now that you have your very own uber, epic, mega lock, you will want to make sure that you don't scratch your bikes to hell with it.  So we used a plastic accordion tubing to wrap around the metal.  If you have access to rubber, or even copious amounts of electrical or duct tape, use that. 

For this, we made one long cut down the length of the tubing so we could slide it over the metal rod. 

Step 8: Lock Your Bikes

Now that you have created uber, epic, mega lock, you can finally sleep in peace knowing your bikes are all safe and sound. 

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    38 Discussions

    I've seen various lock busting videos... I am so paranoid! That is why i have ANOTHER cable lock too. hahah

    I'm about one more bike steal away from just hiring someone to stand in my bike yard.


    Reply 5 years ago

    Why not an automated turret? When it works you can loot the thieves and make money off of it for a bike tracker.


    7 years ago on Step 2

    That is a nice, custom lock that you have created. One hint is that most thieves carry either chain cutters or cable cutters. Most thieves do not carry both. So also use a chain.
    Having said that there is no padlock like device that will stand up to two minutes of attack if a thief knows what he is doing. One answer is long prison sentences for the first instance of bicycle theft. Knowing that stealing a bicycle will be a life ruining experience will tend to stop most sane people from such a crime. Thieves are the greatest obstacle in getting people to use bicycles and not use cars. The theft of a bike is actually an assault upon all of society. It is in effect, a form of terrorism that alters society just as bombs and bullets do. Matter of fact more people die in bicycle thefts than in bank robberies. It is a serious crime but treated as a joke by the law.

    2 replies

    Reply 7 years ago on Introduction

    Thanks! I totally agree. Scary to think people die over bikes though. In regards to this i'ble, this lock is mainly a cost effective way for us to refrain from buying 3-5 U locks, ontop of the cable lock.

    we do use two types of locks for this set up (modified lock, and a cable lock). We also installed a motion sensor flood light right above the bikes. I want to attach a red LED light to it as well for added funsies. Then when the light goes off, and the potential perps see the little red LED, they think its a camera attachment as well.

    Add it to the laundry list of "To Do" Projects in my house. :D


    Reply 5 years ago

    I think I will skip a bike lock and use an informative pamphlet instead. I believe it may scare them more, kind of like training a cat with a spray bottle.


    7 years ago on Introduction

    Well, I used to use a truck-sized steering wheel club on my Honda, and they laughed at that but it never got stolen.

    This is a question for the welder, wouldn't it be better to cut the stock on a matching bias and at different spots on the length and then weld them for a stronger joint? It seems you have hardened steel that just meets up at a point and then you fill in with weaker welding metal. It would probably be easier to just crack and snap the joints if they saw the weld.

    1 reply

    The welds are ground down, and then painted over to create a seamless finish. And then to add to it, we covered the entire metal bit with tubing, so you can't see the two welding points, even if we had left them as is.

    I guess you could have the welding points at different spots to prevent someone trying to snap or crack at the joint, but if someone came in, ripped the tubing off, snapped giant rods of steel, took four bikes, jumped over my fence with them, and then rode off into the sunset... bravo! They deserve the bikes at that point! That is dedication hahaha


    7 years ago on Introduction

    While I do applaud the creativity, pelase do not confuse this as a means of actually protecting your bike any better than any other lock system out there. The weakness is still in metal - commercial locks just don't make them thick enough or dense enough to thwart a determined thief. And that is understandable, since who wants to carry a lock that is heavier than the bike itself!

    As I work with a cycle-taxi company, sometimes we have to retrieve stolen taxis or hotel rental bikes. So we have a battery-powered mini circular saw with steel cutting blade. Goes through the same kind of metal locks and steel in about 20-30 seconds on average.

    Saw: $300 USD (average)
    3 bikes: $300-$500 each for the cheap ones (average)
    profit: $600-$1000 and the saw pays for itself on the first useage.

    Indoors or in a locked garage is usually the better 'addition' to make it harder to steal. Can always hang the bikes from a wall or ceiling if you need space - and can become 'wall art' ! :-)


    7 years ago on Step 8

    Hi, Thanks for posting this and sorry you had bikes stolen. I've lost a couple myself and found it to be a very trying experience.
    My interest for commenting is your headline and last photo that shows three bikes vertically mounted, how? Is this some propriety device you can point me at or do you need to write me another instructable ;-) Al

    1 reply

    Reply 7 years ago on Step 8

    It totally sucks! Sorry that you have had to go through this.

    As for the bike rack, you are in luck! Good old fashioned store bought rack that bolts into the studs on your wall. We have these at the Instructables HQ also.

    The one I have is made by rubbermaid, and you can probably just google "Rubbermaid vertical bike rack" and see what pops up!

    Good luck and thanks for checking out my i'ble!


    7 years ago on Introduction

    Bike and motorcycle thieves usually don't carry cutters for all situations. Some have chain cutters while others have cable cutters while others attack the lock portion. It can be wise to combine a chain and a cable in such a way that they would need more than one tool. Usually they will go for the easy targets and in general avoid hard work. That is why they are thieves to begin with.

    1 reply

    Reply 7 years ago on Introduction

    They also want to get in and out quickly, which is related to but not the same as easy.

    Personally I use a piece of snig chain on my bike stash. The chain passes through two holes in the wall then fastened by a decent padlock which is inside the garage.

    8mm snig chain could be cut but not in reasonable time by hand-tools.


    7 years ago on Introduction

    You need to ride uglier bikes.

    I've found that the more cool stuff on a bike the more likely it is to walk off. So if you don't *need* a drink cage and front shocks, etc then don't have them.

    Quick release anything is just asking to be quick-released.

    Black bikes are more stealable than coloured bikes. Clean and shiny bikes are worse than beaten up ones.

    So my bike has a scummy looking water-damaged cardboard on a carrier instead of a flash mudguard/fender. It has no flash light fittings permanently attached. The handle grips are crappy foam. But the bearings are perfect, rims are true, brakes work stunningly, and the tyres are properly inflated.