How to pick a poor quality combination bicycle lock

Introduction

Recently my friend Francis had a bicycle lock of the cheap variety. However, he couldn't use it because he had forgotten the combination. I had a look at it, and within a few minutes I figured out the combination and opened it. Even more recently than previously stated, I found a lock of very similar characteristics. It looked almost brand new. I gazed off into the distance and surmised that some poor student had bought the shiny new lock, thrown away the packaging, and subsequently forgotten the combination. I took the lock home with great joy, and shortly thereafter it was unlocked. In this document I will explain what I did to discover the combination.

Please note that I'm not writing this to aid in the theft of bicycles. I despise bicycle thieves and have had my very expensive downhill mountain bicycle stolen while inside a shop downtown Victoria. I am writing this because I believe in the freedom of information and that by providing this people may become aware of the benefits of a good quality lock.

Required Items

All you need to follow along is a combination bicycle lock like the one pictured in Figure 1. I don't know how much they cost, but I would guess you could buy one for about three Canadian dollars. Notice the very skinny chain links. It wouldn't take much to snip through this lock with a pair of pliers (or even scissors for that matter).

Figure 1: The common cheap combination bicycle lock.

Step 1: Preperation

Grasp the bicycle lock in both hands so that the indicator (the little mark that shows which row of numbers are the combination) faces up and towards you. Wrap your fingers around the chain and pull slightly so the combination mechanism remains taught as if you had the correct combination and you were about to pull the lock open (see Figure 2).

Figure 2: Holding the lock in preparation.

Step 2: Left-to-right Search

Starting with the first dial (presently a 3 in Figure 3), cycle the dial while maintaining a slight pull on the mechanism. As you go through the numbers, watch for a loosening between the current dial and the dial to the right. This loosening is represented by a slight space between the dials. The space will be subtle, but definite. When you see the space, this means you have selected the correct number. Figure 4 shows the space between the first and second dial. The correct number for the first dial is 6.

Figure 3: Beginning the left-to-right search at the first dial.

Figure 4: A space appears between the first and second dials, indicating that 6 is the correct number for the first dial.

Being careful not to move the first dial, begin searching the second dial for the correct number. Repeat the procedure above, looking for a space between the second and third dial. Figure 5 shows the beginning of the search, with no space between the second and third dials. Figure 6 shows the end of the search, where the dials seperate, leaving a space, and indicating that the correct number for the second dial is a 6.

Figure 5: Beginning the search on the second dial.

Figure 6: The seperation between the second and third dials, indicating that 6 is the correct number for the second dial.

Again, being careful not to disturb the first and second dials, repeat the step for the third dial. A space will appear between the third and last dials. Figure 7 shows the space and the correct number 4.

Figure 7: The space between the third and last dials.

The search for the last and final dial is simple. When you hit upon the correct number the lock will pop open as seen in Figures 8 and 9.

Figure 8: The search for the final number, 6.

Figure 9: Finished! Free lock!

As demonstrated, the process is quite simple and easy. If you are concerned about the quality of your lock, complain to the store where you purchased it or to the manufacturer directly. Or better, return it and demand a refund. Always lock your bicycle. Even a cheap crappy lock like this is a deterrent for potential thieves, but if someone really wants to steal your bike, there isn't much that will stop them.

Please don't steal bikes. And especially please don't steal whatever I lock up with my lock now that you know the combination is 6-6-4-6.

Copyright 2005 Donn Morrison

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