How to Open a Four-Digit Combination Lock

Hunker may earn compensation through affiliate links in this story.
Image Credit: tombaky/iStock/GettyImages
See More Photos

With all the passwords, usernames, and entry codes you need to remember as you go about your day, remembering the code to a combination lock can be tricky. If you have forgotten the sequence to a four-number combination lock, it doesn't mean the lock is no longer useful or that your item is forever secure. There are a few ways to safely open an otherwise secure combination lock.


Video of the Day

4-Digit Combination Lock Details

Simple yet effective and more secure than their three-digit combination lock counterparts, four-digit combination locks are made to last. There is one wheel for each number. When the dial is turned, the spindle that connects each wheel rotates the drive cam. A drive pin that is attached to the drive cam makes contact with the tiny tab on the wheel fly that is adjacent to the wheel.


There is a wheel fly on each side of each wheel. The drive pin is responsible for having all the wheels make contact. When the correct combination is entered into the lock dial, all the notches on the wheels line up on the spindle and the lock pops open.

How to Set the Lock

To set a combination lock, place the dial at 0 to begin. Use the reset tool that came with the combination lock if you have it. Most locks come with reset tools, although many bike locks do not. If you don't have the reset tool, you may be able to get it from the manufacturer. If you have the reset tool, push it into the hole on the side of the lock chamber. Turn it 90 degrees in either direction. Set the wheels at the combination you've chosen. Try to choose something easy to remember and specific to you but that isn't easy for others to guess, such as a birthday.


Remove the reset tool, and your lock is all set. Some of the more reliable locks on the market include Puroma and Master Lock. The Puroma combination lock instructions are readily available online for troubleshooting or setting a four-number combination lock.

If the Lock Doesn't Work

A good combination lock can make you feel secure when you have to walk away from your belongings or ensure that they are safe while you sleep or work. When it refuses to open to allow you access to your things, it can be frustrating.


If you forgot a bike lock combination or the digits to a padlock with a dial, you can try to reset it. Pull on the shackle until you see the wheels turn. When the wheel sticks or catches, move to the next wheel and continue through all the wheels. They will barely stop at the combination, so this process takes quite a bit of patience.

If your lock has a serial number, you can contact the manufacturer and fill out a lost combination form, which you can print from your lock manufacturer's website. You will then need to have it notarized and mail it in. This process may take several weeks. You can also try visiting the distributor or retailer where you bought your lock, although some retailers may charge a fee for this service.


Report an Issue

screenshot of the current page

Screenshot loading...