BMX bikes are one of the coolest bicycles in the market. They allow you to do amazing tricks and show off your riding skills at the park or out on the streets. But to perform insane tricks and impress others you need the perfect size for your BMX bike. 

There are different sized bicycles for various individuals. So, for example, if you are buying a BMX bike for a 12 year old adolescent, you will need the right size for them. If you buy an adult size BMX for a child they won’t be able to ride it properly, and they could harm themselves by getting into an accident. 

BMX bike sizes start from 12 inch tires and go all the way up to 24 inches. So, you really have to hit the mark with the bicycle size.  

Here we will discuss the perks of getting the right size for your bicycle. We will also talk about why size matters in this case. 

BMX Bike Size Chart 

Rider Height

Rider Age (Avg.)

Rider Weight

Frame Size

Top Tube Length

Tire Size

2′4″ to 3′0″ 

5 and under 

< 60 lbs

Micro Mini

< 18”


2′8″ to 3′6″ 

5 and under

< 60 lbs


< 18”


3′2″ to 4′0″ 

5 to 7

Up to 75 lbs




4′0″ to 4′10″ 

10 to 13

Up to 130 lbs


18” to 18.5”


4′10″ to 5′3″

10 to 13

Up to 150 lbs

Expert XL

18.5” to 19”


5′3″ to 5′6″ 

10 to 13

Up to 150 lbs

Expert XL

19” to 19.5”


5′6″ to 5′9″ 

13 and over



20.5” to 21”


5′9″ to 6′0″ 

15 and over


Pro XL

21” to 21.5”


6′0″ to 6′3″

15 and over




20” to 21”

6′3″ and over 

15 and over



21.5” +

21” + 

Importance And Benefits Of Choosing The Right Size BMX Bike 

Choosing the right size BMX bicycle is beneficial for the rider and helps in performing amazing tricks as well as stunts. BMX sizes vary from person to person and the size depends on the individual’s height.

The weight, tire size, and the bike’s material can also be factors. But before we get into that let’s talk about the benefits of choosing the right BMX size for you.

Related Article - Best BMX Bikes For Beginners

Reduces Chances Of Injury

When you get a bicycle that fits you best, you have more control over your riding. As a result, you do not get into many accidents and consequently have fewer injuries. That’s beneficial in the long run and especially if you decide to go pro in the future.

If you have injuries from your past outings, you will find it difficult to compete at the highest level. After all, fitness is everything for an athlete.

Better Handling

Have you ever ridden a child’s cycle while being an adult? Let us tell you, if you haven’t you should try it just for fun. But apart from having fun you will learn a thing or two about riding the right size BMX bicycle. You will experience that handling is an issue with a smaller bike and that it is unsafe to ride one professionally.

Not only will you find it difficult to balance the bike but you will also have trouble keeping it upright. On the other hand, if you buy an adult BMX bike size you will discover performance, improved handling and control.

Ease Of Portability

How does it feel when you pick up luggage that’s double your size? It gets uncomfortable, right? Well the same goes for BMX bicycles. Generally, the taller you are the easier it will be for you to transport your bike. A bigger bicycle will be heavy and difficult to carry. So, it helps if you choose the right size from the size chart. Otherwise, you will require external help every time you want to pick up your BMX bike.

Easier To Do Tricks

All the stunts performed on BMX bicycles depend on your ability to control and lift the bike with ease. If you are a thin individual with a large bicycle, performing stunts won’t be very easy. But if you have the correct size BMX bicycle, things could get a lot easier.

Related Article -  11 Easy BMX Tricks You Need To Try

what size bmx bike do i need

How To Measure A BMX Bike

You have read the importance of getting the right size bike for yourself, now it is time that you learn how to measure one yourself. If you are visiting a store to buy one, it is better to consult a size chart and compare it with your dimensions so you can measure correctly.  

The measurements can help ascertain the perfect BMX bicycle for you. The tire size is extremely important but you should also consider the frame dimensions, the distance from the seat tube to the handle bars and other things. Here is a step by step guide on how to measure a BMX bicycle.  

  1. 1
    First, you must gather all the necessary tools for the job. In this case, all you need is a tape measure that shows measurements in inches.
  2. 2
    You can start with the tires and measure their diameter in full. The size chart will tell you the one which suits you best. So, make sure you fall within that range. It is quite easy to measure a tire. All you need is to hold the measurer on one end of the rim and compare it with the number on the other end. You have to go through the center of the wheel to get the most accurate measurement. 
  3. 3
    Next up is locating the seat tube and measuring its height. For this, locate the top of the seat tube where it holds the seat in place. From there downwards, measure to the point where the tube connects with the pedals. That’s the seat tube length and it will determine how high you sit on the BMX bike. If you are too low or high, the offset will disturb performance.
  4. 4
    After that, you must consider measuring the top tube and the distance it has from the seat tube to its connection to the front axle. In simpler terms, this will measure the distance between the seat and the handlebars. You want enough space to fit your feet, while pedaling and sufficient space to hold the handlebar. The last thing you want is the top tube to be short or too long. It is the major concerning factor for BMX bikes, so be careful.  
  5. 5
    On the other hand of the spectrum is the chainstay length. It is the distance from the pedal sprocket back to the point where the chain is attached. You don’t want the chain length to be too long or short. If you ask professional BMX riders, they will tell you that the chain length can have a huge impact on the bicycles performance. Therefore, ensure that you are going the correct size prescribed for your body.
  6. 6
    Moving on, the next part is to measure the total height of the bicycle from the ground leading up to the top tube. This will be your bicycle’s ride height and it will determine how comfortable you can keep your feet on the ground when resting during tricks. You don’t want it to be so high that you can’t place your feet flat on the ground while sitting on the seat.
  7. 7
    Seventh on the list is measuring the size of the handlebar. So, you take the tape measure and mark to the nearest inch the height from the point where the front wheel attaches the frame to the handlebars. Once again, this measurement has to be perfect.
  8. 8
    After you have measured all the parts, you should draw a rough sketch of the bike and write the measurements in their right place. This will help you classify the various measurements and you won’t confuse yourself when in the shop. 

The Most Important Measurement – The Wheels & Top Tube

We talked about quite a few areas that one should measure before buying a BMX, but out of all of them, the wheel and the top tube measurement is the most important. Why? Well, that’s because the wheel size shows how high you are from the ground and the top tube length ensures you have ample space for your feet. When you are pedaling, the feet rotate forward and they can touch the handlebar if you don’t have the right size.   

So, you must keep in mind that there is sufficient space for your legs to fit. The chart at the end of this article will show you the relative top tube measurement concerning your height. Furthermore, it is interesting to note that the height matters the most when searching for an adult BMX bike size.  

bmx bike size top tube

Other BMX Bike Part Sizes

As discussed earlier, the wheel and the top tube are the most important measurements. But other parts also play a role in the bike’s performance.  We will look at a few of them here.

Crank Arm Length

The crank arms rest between the pedals and that is where the pedals attach. You have to ascertain their length based on your riding style and comfort. Longer crank arms make the pedals wider and you have to ride with a open feet. It can get a bit uncomfortable if you have the wrong length. So, try different lengths and check whichever suits you best. 

Fork Offset

The fork is the part which attaches the handlebar to the front wheel. But the point at where the fork attaches the rim, there are two u-shaped ends. They can be vertical with the fork or they can be horizontal. That is what we call the fork offset. If it is vertical to the fork, there is zero offset. Otherwise, we have various offset measurements to choose from. It all depends on your preference but usually close to a zero offset is best for a beginner rider.

Handlebar Dimensions

The handlebar also has to be the perfect size. So, its height and width are of extreme importance. Too much width or too less width can affect bike control. The height has more to do with your comfort. So, sit on a BMX and compare the sizes. Buy whatever suits you the best.


The bearings in a BMX bicycle are small metallic balls that are fitted inside the wheel hub. They allow the bike to run smoothly without friction. You must ensure you have good quality bearings installed so that you can perform tricks and stunts with relative ease.

Frequently Asked BMX Bike Size Questions

What age is a 20-inch BMX bike for?

The 20 inch wheel size is for adults and specifically for individuals that are 150-160 cm tall. Such heights are usually reached around puberty. So, a person that is 14-15 years old can use 20 inch tires. 

Learn More - Can Adults Ride 20-Inch BMX Bikes?

What age is 26-inch BMX bike for?

BMX bikes with 26-inch tires are too big for children. They are well suited for individuals who are young adults. So, people 19+ years old. 

How do I know what BMX frame size I need? 

You can check the BMX size chart above to find out the frame size you need. Generally, the taller you are, the bigger frame you will need. 

What is the standard BMX bike size? 

The standard BMX size is 20 inches more or less. So, the tire size is 20 inches and the frame along with the other measurements are relative to that. But make sure to consult the BMX bike sizing guide for insight. 


So, what size BMX bike do I need? There are so many different sizes of BMX bikes on the market. It is important you choose the correct size, so you can be comfortable and progress in your riding technique and skills. We hope this article helped breakdown all the different sizes and the riders they are best suited to.