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Why are BMX Bikes so Small? (Reasons Explained!)

Don’t let the size of BMX bikes fool you. They may look small but there are sizes available for all ages. They have been in the market since the 1970s and are still trending, especially among youngsters.

They are popular for their ability to do tricks, jumps, and for urban riding. They have three types of riders, BMX racers, BMX freestylers, and dirt jumpers. 

Why are BMX bikes so small?

BMX bikes come in various shapes and sizes to suit different ages. Most of them are thought to be small because of their popularity among youngsters. They are small in size so that they can reduce the overall weight and perform stunts and tricks better. 

Are BMX bikes supposed to be small?

Not all BMX bikes are small. The smallest sizes are Micro Mini, Mini, and Junior. These sizes are specially catered for kids. They are smaller than Mountain bikes and the small sizes are as small as Road bikes. 

Most of them can look small because of their weight. They’re usually lightweight because they don’t have too many components. 

There are bigger sizes as well made for adults who are even above 6 feet in height. What matters is the top tube length and wheel size. 

Four reasons why BMX bikes are so small:

In order to reduce the weight:

Bike riders are always looking for lightweight bikes to increase their speed. This is why most BMX bikes tend to be lightweight around 10 to 28 pounds.

Some are as light as Road bikes and others can weigh as much as Mountain bikes. BMX bikes don’t need many parts when compared to Mountain Bikes. 

To be able to do bigger jumps:

This is why BMX bikes seen in the Olympics are so small in size. The smaller the size, the bigger jumps you can do!

In Olympics BMX cycling, riders have to be able to handle the impact of landing after the jump and this is why lightweight bikes are needed.

To perform advanced stunts and tricks:

Just like jumps, it makes it easier for you to move around with your bike when you’re stunting.

The smaller the bike is, the less it will get in the way when you’re performing tricks. It makes the bike more responsive. A shorter top tube also enables you to spin quicker. 

They were initially designed for kids:

At first, it was only targeted for children from the age of 6 to 17. But slowly, adults started using them but the design never changed.

This is why it’s so small. But they have increased the frame size and wheel size for many sizes. Now you can get customized ones as well if you still feel that it is too small for you. 

Why do BMX bikes have small cranks?

BMX crank length is from 145mm to 190mm. But most BMX riders pick shorter cranks about 165mm. This is because of freestyle BMX riders. Shorter cranks enable clearance when performing tricks. 

The shorter the length of your cranks, the more closer your pedals will be to the center. This will make it easier to catch them when whipping. It will also spin quicker compared to longer cranks. 

Short cranks are mostly popular with BMX racers and flatland riders. Companies such as Profile manufacture them. It also saves you some weight, making your BMX bike lighter. 

Why do BMX bikes have small wheels?

BMX bikes often come with small wheels. Why? Let’s find out.  You’ll see some wheels that are only 15 to 16 inches in BMX Micro Mini bikes. But the most common and popular size is 20 inches. Here are some reasons why BMX bikes have small wheels. 

Faster acceleration and speed due to the reduced weight:

Smaller wheels come with fewer spokes which makes them create less friction compared to larger wheels. Many Olympic BMX racers use small wheels for racing. It will be easier to ride during traffic as you will need to stop repeatedly so fast acceleration is necessary.

It is easier to move around:

It will make aerial and flatland tricks simpler due to its added maneuverability. Especially when it comes to sudden turns and wet areas. Your bike becomes more responsive as the tires get higher pressure on the road. Overall, it results in a more maneuverable and stronger bike. 

More portable:

Due to its small size, it can be kept anywhere simply whether it is in an apartment or a car, or the garage. It will take up less space as well. As a result, you’re saving space! 

However, you will find larger wheel sizes such as 24 inches which are mostly seen in BMX Cruisers which have the same maneuverability and set up as the smaller ones, making it advantageous for all riders. 

Why do BMX bikes have small sprockets?

Large sprockets bend easily when in contact with an object compared to small sprockets. They bend less easily. Small sprockets are sought by flatland riders as they make performing tricks easier.

It is likely to hit other objects during stunts which mean less damage occurs to the sprockets. 

Moreover, weight is a factor. Small sprockets are lighter which reduces the weight of the bike. Not only are they stronger, but they also look better which is why small sprockets can be seen in many bikes recently. 

Having large sprockets will make your chains break more than usual when compared to small sprockets.

Is a 20 inch BMX bike small?

That is the average BMX bike size. You should be at least 5 feet and 3 inches tall to ride a 20 inch BMX bike. This is more suited for intermediate riders and not the best choice for BMX racing and professional riding. 

However, this is not a small BMX size because there are smaller sizes available for kids. 

The suggested rider weight for this size is around 110 to 150 pounds. Any more than 200 might make it uncomfortable for you to ride it. If you weigh more than that, you should go for Pro XL which has a frame size of 20.5 to 21 inches. 

Can adults ride 20 inch BMX bikes?

Adults can ride 20 inch BMX bikes. This is the standard size that can be used by anyone over the age of 10. This size is from the size category BMX Experts and Pro. It’s not the best option for professional riding as it cannot withstand high amounts of pressure. 

If you’re into stunting and performing tricks, go for larger sizes. Younger children can also use this size but it comes down to their height. They should be over 5 feet tall. 

Are there different size BMX bikes?

BMX bikes typically come in 8 different sizes and they are Micro Mini, Mini, Junior, Expert, Pro, Pro XL, Pro XXL, Pro-XXX, and Cruisers. 

Here is a breakdown of each size for a better understanding. 

Size(Name, Frame, Wheel) in Inches
Micro Mini
Bike Frame Size: 15 to 16 inches
Wheel Size: 16 inches
Bike Frame Size: 16 to 17 inches
Wheel Size: 18 inches
Bike Frame Size: 17 to 18.5 inches
Wheel Size: 20 inches
Bike Frame Size: 18.5 to 19.5 inches
Wheel Size: 20 inches
Bike Frame Size: 20 to 20.5 inches
Wheel Size: 20 inches
Pro XL
Bike Frame Size: 20.7 to 21 inches
Wheel Size: 22 inches
Bike Frame Size: 21.5 to 22 inches
Wheel Size: 24 inches
Bike Frame Size: 22 inches
Wheel Size: 24 inches
Bike Frame Size: 21.5 to 21.75 inches
Wheel Size: 24 inches

How to choose the right size BMX bike for you?  

There are certain factors you should consider before selecting the size for your BMX bike.


Your height is the most important factor when it comes to choosing your BMX bike. The longer your legs are, the bigger the size will be of your BMX bike.

If you have a height below 5’4, then you should go for small sizes such as Micro Mini, Mini, Junior, and Expert.

For anything above that, go for Pro, Pro XL, Pro XXL, Pro-XXX, and Cruisers. If you have a height of 163 then you should go for the standard size, bike frame, and wheel size of 20 inches. 


Although BMX bikes don’t have an official weight limit, you should take note of your weight. Micro Mini, Mini, and Junior sizes cannot take more than 150 pounds at max.

All BMX bikes, in general, have a weight limit of 300 pounds but some specific brands make BMX bikes for overweight people. 

Your Experience:

Your experience also counts. You should ride a regular bike before buying a BMX bike. If you’re a beginner, go for frame sizes that are less than 20 inches. BMX expert is for middle-level riders who are about 140 cm in height. 


Anyone less than the age of 6 should not be riding a BMX bike for safety issues. Kids under the age of 12 should get bike frames that are 15 to 18 inches and should have smaller wheels than adults. 


The place you will be riding matters too. If you are planning to ride in parks, smaller sizes are appropriate but for public places with traffic, larger sizes are suggested. 

Riding style:

If you’re a freestyle rider who rides in parks and off-track roads then short top tubes should be enough. Dirt riders will need longer top tubes which are at least 20 inches. 

Just like us, BMX bikes come in various shapes and sizes. It doesn’t matter what your weight, height, or age is. You can always get a BMX bike that fits you. There are many brands and sizes available for everyone. Go to a local bike shop to figure out what’s best for you. 

Frequently Asked Questions:

How can I make my BMX bike faster?

Are BMX bikes good for adults?

Can you sit on a BMX bike?

How much weight can a BMX bike hold?

Does BMX size matter?

Does BMX tire width matter?

Are BMX bikes heavy or light?