If you have spent any time with a bicycle, you likely have noticed the gears. Many bikes nowadays, and likely the one you have, has a ton of different gears, even up to 21 and 24 gears. So you ask yourself, “Why do bikes have so many gears?”.

Many bikes primarily have gears to allow you to have a comfortable experience when riding your bike on a variety of grades. They also make things smoother when shifting, and even make it so that your pedals don’t spin freely when you are going faster than your current gear will allow for.

To allow for a comfortable ride, no matter the grade

Have you ever been riding a bike and it just became too difficult to pedal and needed to walk? That is where gears come into the picture.

Once it becomes difficult to pedal, you can quickly change to a lower gear, and it results in you being able to pedal with less resistance.

You may not cover quite as much distance, but it will be a lot easier, and take less energy.

The more gears, the smoother shifting from low to higher

Adding more gears to a bike allows for a smoother transition from lower to higher gears. Basically you won’t have quite as large of a jump between gears from one to the other.

So you don’t spin freely when going quicker

One thing that is a real pain, is when you get going fast enough that you aren’t able to catch the gears and continue to accellerate.

Having more gears means you can go up a gear, and continue to pedal without it spinning freely.

Different gear combinations

While many people probably aren’t aware, there are plenty of different gear combinations out there!

Below are some of the most common combinations!

Single Gear

This is an extremley common style of bike in cities. It only has one gear, which means you don’t ever change the gear, no matter if you need to or not.

It is extremely simple, and extremely reliable.

1×7 (7 gears)

This style of bike has 7 gears in the rear of the bike, and one in the front. I have found this allows for some great reliability, while still allowing for some changes in the gears.

3×7 (21 gears)

I would say most of the bikes you have seen have been the 3×7 combination. This has 3 gears in the front, and 7 in the back.

You find these mainly in mountain bikes, and less so in cruisers and other more simple bikes that don’t need to change gears quickly.

If not taken care of, having this many gears can tend to cause some reliability issues.

Other gear combinations

While the ones we have talked about are the most common options, there of course are many others such as a 2×11, 2×10 and a 3×8. Each of these have their own purposes, but just aren’t quite as common.

Frequently Asked Questions

Why do cheap bikes have more gears?

Like most things in the world, when someone wants to sell something inexpensive, they make it look impressive with a lower quality.

That is why you find many inexpensive bikes trying to imitate higher end bikes by offering things like rear suspension, or a ton of gears.

I’m not saying all bikes are that way, but I think it plays a big part.

Why do bikes have 2 sets of gears?

You will find both a set of gears on the front around the pedals of a bike (aka the chainrings, or a crankset), as well as a set of gears on the rear of the bike (aka the cassette).

The front crankset tends to have larger gears, while the rear cassette tends to have smaller increments.

These both work together to offer a much larger range of gears (like 21 and 24 gears) than you could have with just one set of gears.

Why do mountain bikes specifically have so many gears?

You will find many mountain bikes out there tend to have the most gears. This is because when you are out on the trails you have to quickly be able to adjust with the varying terrain. 

One moment you can be going over a small hill, and the next going down. Because of this you need to be able to quickly switch between higher and lower gears, and be able to have many gears in between to give you optimal power.

Is 7 gears enough on a bike?

For most people a 7 gear bike, which is generally 1 gear on the front and 7 gears on the back is great for many people.

Having fewer gears generally means lower maintenance, and less issues.

Personally, I find I have the most issues with my front crankset on my bike, so it would be nice to have those less gears.

If you don’t change your gears on the bike often, and don’t mind having more dramatic differences in your gears, a 7 gear bike will be just fine.

How many gears do you need

Now that we have dug into what different gears are for, and why they are there, what is the right combination for you!

The short answer is, if you plan on only riding around a city with flat streets, or just around town, I would probably opt for less gears, like a single gear, or a 7 gear bike.

On the other hand, if you plan on spending any time off-roading on your bike, then something like a 21 gear, or 24 gear might be right up your alley.


I hope this article has shed some light on why bikes have so many gears, what gear bike you may need, and that you have learned just a little bit more about bikes in general!

Bicycling is a lot of fun, and can even be a way of life, I hope you enjoy it more while reading through this site.