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Losing the key to your bike lock or forgetting the code to a combination lock can be a frustrating experience.
If it happens while you’re away from home, it’s an absolute nightmare!
In this article, I provide practical advice on how to open a bike lock without a key.
It goes without saying that we do not condone bike theft, and in this article we provide no information that wouldn’t already be known by bike thieves.
Unfortunately, the same locks that frustrate bike thieves may end up frustrating you, but I know with the right tools or some knowledge you can free your bicycle, and the panic will end!
How To Pick A Bicycle Lock
Using Specialized Picking Tools
Lock picks can also be used to open your lock, though you’re unlikely to have these available in an emergency situation.
Many types of lock picks exist.
You also need a tension wrench to place the lock plug under tension while picking it.
Watch YouTube videos from creators like the Lock-Picking Lawyer to learn technique.
Opening A U-Lock With A Bic Pen
This pen trick created controversy in the early 2000s when it worked on Kryptonite U-locks.
For this method to work, you need a bike lock with a tubular core. It relies on a simple design where all the spring tensions do not differ within the locking mechanism.
A more efficient improvised lock pick is an impressioning tool. Like an impressioning tool, a pen moulds itself to the different pin lengths within the lock.
The process goes like this:
1. Find A Pen
Find a pen with a similar or slightly smaller diameter than the lock opening. It has to be a made with a flexible, yielding plastic. Brittle plastic won’t work.
A snug fit helps to create tension inside the lock, which will help you to turn the barrel. Remove the end-plug and the ink tube from the pen.
2. Add Notches
Cut four vertical notches along the pen using scissors. These notches should run along the pen’s sides to maintain flexibility when inserted into the lock. This flexibility helps the pen to conform to the shape of the lock and bypass obstacles.
3. Insert Pen
Slide the modified pen into the lock’s opening as far as possible. Apply pressure if necessary. If the pen doesn’t slide in due to a jammed lock, consider lengthening the notches or cleaning any dirt or rust inside.
4. Apply Pressure
Apply pressure and wriggle the pen clockwise and counter-clockwise inside the lock until it pops open. This can take anything from a few seconds to two or three minutes to achieve. This method won’t work on more sophisticated bike locks.
Video: Opening An Old Kryptonite U-lock With A Bic Pen
Using A Shim On A U-Lock Or Padlock
You can unlock some bike locks without picking them, technically speaking. A shim renders some locking mechanisms useless. What is a shim? It’s a thin piece of metal that slides inside the lock to engage the locking mechanism.
You can open many a padlock (especially combination) using a thin metal shim. This is slid down the padlock shackle into the inside of the lock, where it pushes the locking latch out of the way to open the lock. It’s possible to make a metal shim out of a soda can.
It’s also possible to shim open a cheap U-lock if it has a spring-loaded locking lug. To do that, you’d slide the shim along the shackle into the hole on the crossbar, then run it around the shackle to open the lock. Avoid a cheap bike lock if your bike is valuable!
Cracking A Combination Lock
One way to open and unlock a bike lock with a combination code is to crack the code.
The way you find the code is to first put tension into the lock by pulling on it from both sides.
Starting at the right with the lock still under tension, turn the numbered dial until you hear a pronounced click. The dial will be harder to rotate than it was in other positions.
Move to the next dial and repeat. By the time you get to the left-most dial, you have a 1 in 10 chance of getting the number right, so just rotate until the lock opens.
Since some combination locks are more sophisticated, with “false gates” that make them harder to crack, cruder methods are quicker and more reliable for a thief.
A false gate is a shallow groove in a combination dial that creates the illusion when decoding that a number might be correct, effectively throwing the picker off the scent.
How To Open A Bike Lock By Force
If you ever intend using the lock again or are optimistic you’ll find the original key again, obviously you don’t want to damage it.
However, it might be a way to go with cheaper bike locks that are due for replacement anyway.
Breaking Open A Lock With A Hammer
One way to break open a bike lock is with a hammer and some canned air. This is especially effective with U-locks or padlocks.
1. Buy A Tin Of Canned Air
For this method, you’ll need a tin of canned air. This is the kind of product you’d normally use to clean your keyboard by blowing dust from it.
The purpose of the canned air is freeze the bike lock and make it more brittle, which makes it more vulnerable to breaking.
2. Freeze The Lock
To freeze a bike lock with canned air, first hold the can upside down. Spray it from close range onto the padlock or the crossbar of the U-lock close to the locking mechanism.
Empty the whole can onto the lock, as one or two short sprays won’t achieve the desired result.
3. Hit and break The Lock
Once you’ve frozen the lock, you need to immediately start hitting it with a hammer. With a U-lock, make sure the lock isn’t in contact with the bike frame while you’re whacking it.
Ideally, the lock should be braced by a fence or other object that your bike is locked to when you’re hitting it. If the lock is resting on a concrete path, that should suffice.
After several blows with a typical household hammer (e.g., claw hammer or ball pein hammer), the lock will often break open.
Prising Open A Lock With A Crowbar
A crowbar can be used to break open a U-lock, especially if the bike is locked to something solid, as this provides leverage. Again, you obviously don’t want your bike frame to be the object creating resistance.
The longer a crowbar is, the easier it theoretically is to break the lock. U-locks are more suited to this method than other lock types (e.g., chain locks).
Cutting A Bike Lock Open
There are several ways to cut a bike lock open. Here are three of the most popular:
Wire cutters can often cut open a cheap cable lock within seconds. Cable locks comprise a bunch of steel wire strands, so it’s easy to understand why this is effective. The blades slice through the strands one by one.
Video: Slicing Through A Cable Lock With Wire Cutters
Bolt cutters would make light work of a cable lock and can be used on weaker chain locks and U-locks. With large bolt cutters, you can gain leverage by placing a handle on the ground and pressing down onto it.
With the exception of a few diamond-rated bike locks, an angle grinder can cut open almost any bike lock within a few minutes. You’d only resort to this method on tougher locks like thick chain locks and U-locks, many of which are resistant to bolt cutters.
Commonly Asked Questions About Opening Bike Locks
Is It Legal to Open a Bike Lock If I Don’t Own It?
Opening a bike lock that you don’t own without proper authorization or legal justification is likely to be considered illegal in most jurisdictions.
How Do You Open A Combination Bike Lock If You Forgot The Code?
You can crack the code of a more basic combination lock by putting it under tension and listening for a distinct click as you turn each of the numbered dials.
Do Bike Thieves Pick Locks Or Force Break Them?
Bike thieves are more likely to force a lock open by cutting or breaking it because they can often do this within seconds and get away.
Lock picking is a skill many won’t possess.
How Do You Reset A 4 Digit Bike Lock
That depends on the design. Usually there will be a button or a lever to press while you reset the number.
Once you release this mechanism, the new number is set.
How Can I Maintain My Bike Lock and Ensure It Operates Smoothly And Avoid Rust Or Seizure?
You’d normally maintain your lock by lubricating it regularly.
If the lock has already seized up with grime or rust, try spraying it liberally with WD-40.
How Do Thieves Commonly Break Bike Locks?
The most common method is to use a concealable tool like wire cutters.
Bolt croppers and angle grinders are also commonly used, though they’re harder to use inconspicuously.
Can A Locksmith Help Me Open My Bike Lock?
A knowledgeable locksmith may potentially be able to help you remove a bike lock, though don’t be surprised if they demand proof of ownership before doing so.