How Many Combinations Do Bike Locks Have?

Cheaper locks have fewer combinations than you think. If you want your bike to be there when you return, here’s what you need to know.


Combination bike locks are a real boon for those of us who have a habit of losing their keys. (Don’t ask me how I know!)

When you don’t know all that much about combination bicycle locks, it’s only normal to wonder if they are as secure as their manufacturers claim they are. I mean, couldn’t someone guess the combination? How many combinations are there on a bike lock?

The number of combinations of a bicycle lock depends on how many dials it has. For example, a lock with three wheels and a number range for 0 through 9 has 999 combinations, while a lock with five dials offers as many as 99,999 combinations. That’s a big difference!

In this post, we will talk about the different types of combination locks—and how much security they provide for your bike.

When you’re buying a combination lock for your bike, we’ll also talk about why it’s important, whenever you have the option, to opt for a bike lock with a larger number of dials (and, therefore, combinations). We’ll even get to how to brute-force a lock whose combo you’ve forgotten.

How Many Combinations Are There On a Bike Lock?

As we already touched on, the number of combinations on a combination bicycle lock depends on how many wheels it has and what’s the number range on them. Thankfully, this is pretty easy to work out.

To work out the exact number for your lock, you’ll need to do a couple of things:

  • Look at the number of wheels on the combo lock
  • Look at the number range on each of those wheels

Most locks have the number range from 0 through 9.

Cheaper locks usually have three wheels, while pricier locks usually have five wheels. Combination locks with four wheels are in the middle range, both in terms of price and the protection that they provide for your bike.

Once you know the number of wheels and their number range, you can work out both the lower range and upper range of combinations for your bicycle lock. To see how it works in practice, let’s take a look at an example.

Say you’re looking at a combination lock with 4 wheels, with the lowest number on each wheel being 0 and the highest number on each wheel being 9.

This means that the lowest combination is 0000 and the highest combination is 9999. This means that you have 10,000 possible combinations on your bike lock. (Since most people never set their bike lock to 0000, manufacturers count it as 9,999 combinations.)

It really is that simple!

The more wheels there are, and the more numbers on each of the combination wheels, the more potential combinations there will be.

Why Get a Combination Lock With As Many Wheels As You Can

40-99,999Good enough

The more wheels your combination lock has, the higher the number of possible combinations it has. The higher the number of possible combinations, the lower the risk that someone will pick your lock.

Combination locks with two or three wheels offer only minimal protection and, since some combinations are more common than others, can be picked by an experienced bicycle thief in a few seconds to a few minutes.

Combination locks with four wheels have 9,999 possible combinations. A bicycle thief would probably need an hour or two of continuous attempts to open the lock. In areas with high pedestrian traffic, this can be difficult. However, in areas with low traffic and/or at night, it’s not impossible.

If you have a combination lock with five dials and 99,999 potential combinations?

Nobody is going to get into that bike lock unless they’re lucky enough to guess your combination. In any case, it would take hours upon hours of trying.

So, if you have a bike that you really want to protect, then getting a bike lock with at least 5 numbers in the combination will protect it as much as possible. Nobody is going to be brute-forcing that lock open.

How to Brute-Force a Combination Lock

What should you do if you forget the combination to your bike lock and can’t remember what it was?

If you left your bike in public, it’s best to go home, get proof of purchase (e.g., the receipt from the bike store) and/or a photo of you riding the bike, and then call the police or the local parking authority and ask for help.

You don’t want to be mistaken for a bike thief and have to prove that you really aren’t one. If that goes wrong, and it does sometimes, it can ruin your day and your record in more ways than one.

Related: What to Do When Your Bike Lock Won’t Open

However, if your bike’s parked outside of your dorm, apartment building, or in your house’s front or back yard, you can try to brute-force your way in.

If your lock has three to four wheels, it should take you 1-2 hours at the most.

You probably won’t be able to do that once you start getting into the 99,999 potential combination territory. In most cases, you are probably going to want to cut the bike lock off. However, you can still try and brute-force it.

On some combination locks, there is a method that could potentially work. However, this method tends to work *only* on the cheaper combination locks. Remember, expensive locks pride themselves on their security. Brute-forcing them is supposed to be impossible (as it very often is).

Step #1: Pull the Bike Lock

The first step is to put a little bit of pressure onto the locking mechanism of the bike. You can do this by gently tugging on the sides around the combination. You may see a bit of movement in the wheels when you do so.

Step #2: Move the First Number

Move the first number until you hear a slight click or you feel the number “catch” on the locking mechanism. We cannot stress enough how this may not work if you have a higher-quality combination lock.

Step #3: Move The Rest Of The Numbers

Repeat the process for the rest of the numbers. Once again, you want to hear a click at each and every turn that catches on the mechanism.

Step #4: Unlock

If you managed to get all the numbers correct, then the bike lock should open. In case you only heard a click on one number, you would have drastically reduced the number of potential combinations you will need to try.

(Oh, and when you’re done, open up your laptop or head on over to the local bike shop and get yourself a good bike lock. If you were able to do this, imagine just how quickly someone who steals bikes for a living would!)

Final Word 

The number of combinations on a bike lock will vary.

The more wheels you have on the bike lock, the more potential combinations there are. A bike lock with 3 reels will likely have 999 combinations (assuming the numbers start at 0), and a bike lock with 5 numbers will have 99,999.

Better quality combo locks will always have more numbers on them. This makes them tougher to crack. So, if you can afford to spend the cash, always try to ensure that you buy a better quality lock. They will act as a far better deterrent than a 999 combination lock which, in most cases, can be cracked in about 10-minutes. 

By Dim Nikov

City dweller. Recreational cyclist with a knack for writing. Always trying to find the right balance between life and bike.