Crack A Combination Bike Lock In Under 30 Seconds

Crack A Combination Bike Lock In Under 30 Seconds

The video shows how to open a standard four-digit bike combo lock by looking for the gaps between the numbers.

Obviously you should only use this hack for your own lock (and not for stealing bikes). It’s a good idea to learn about lock picking of all kinds to increase your security knowledge.

If you’re looking for a more dependable lock, check out REI’s guide to choosing a bike lock and the BBC’s bike security tips.

How to crack a combination bike lock in under 30 seconds [WonderHowTo via Reddit]


  • Sorry to burst your bubble there is a much easier and quicker method that my friends and I used over 20 years ago that works in the dark or even without looking as long as you know which end to start.

    Pull the two chains lightly putting tension on the lock and rotate the first number, when it suddenly feels free the roller is in the right spot, repeat for numbers 2-4. It will take you about 10 seconds to “crack” the lock that way.
    You can also remove the retaining clip and change the order of the numbers trying the 24 different combinations until you find the one that resists this technique the most. Then if your really obsesive you can sandpaper the pins changing the clearance so you can no longer work from 1-4 making it slightly harder.

    BTW neither of these techniques work on the 5 digit comination locks.

    • Haha, i was about to write the exact same thing. I figured this out myself a few weeks ago when I forgot my bike lock combination. Just put some tension on it and started flipping the combination numbers around until it opened. took about 15 seconds!

    • Yup – works like a charm this one – saved me only a few weeks ago when I got my stuff out of storage (turns out I was one digit out but couldn’t remember and it was getting dark and still had heaps to move). The gap method does work but is much harder and doesn’t work on all combo locks.

      BTW a key is MORE likely to get lost than forgetting a combo I have found, but they are more secure.

  • My son lives with his mom visits limited. I lost combo and he did as well. This helped me open his lock so he and a friend could go and not worry about someone stealing their bikes. I’m not interested in taking what is not mine
    Just preserving what is

  • Hi,
    Pulling both sides of the lock method, i am trying for my cycle ( i wrote the lock number and saved as a contact in phone and recently had a phone reset to improve performance :)), out of the 4 rings, first and second rings are very loose whatever their number are and the 3rd and 4th are always tight again irrespective of their numbers. any help.


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