How To Build A BMX Bike

Author: Alex Bristol

Last Update:

Are you ready to step up the game and make your own personalized BMX from scratch?

Building your own BMX is quite a challenge, but the results are well worth it. That’s why I’m going to take you through the whole process from A to Z so you can build your own BMX bike.

So, you’ve reached that point as an advanced cyclist where you’ve tried every basic maintenance trick in the book, the simple DIY stuff just doesn’t cut it anymore. And neither does a standard complete BMX bike.

Ready for a challenge?

Learning to build your very own BMX bike is a pretty significant milestone for a BMX rider. Even the best BMX bikes have limits, but when you build your own from scratch you get to decide where the limits are.

I’ve got you covered. In this article, I will discuss everything I wish I had known when building my first BMX bike. From the tools needed, and bike parts to guiding you through every step of the process so even the more adventurous beginners can have a go.

Whether you want to build your bike entirely or replace some parts, customizing bikes is well worth it and easier than you think.

Let’s go!

A man jumping through the air while riding his BMX bicycle

Check the Cost

How to build a BMX bike on a budget?

Before you get stuck in, are you sure you have the funds to be able to finish the job? You’ll need to decide if you’re changing an individual part, or building an entire bike. The cost for each part can vary depending on if you buy new, used, which brand, and type. From scratch, you’re looking at $1700 roughly for the whole bike, but it also depends on how high quality you want to go or if you prefer cheap bmx bikes. You’ll need to double check if the parts are compatible with the bike too.

If you want to build a BMX bike on a budget, then I’d suggest getting second-hand parts and upgrading bit by bit until you have a new bike. Cut down costs by choosing a couple of good quality parts on things that matter to you.

A few bike parts and tools

Everything you need to build your BMX bike

Main bike body

  • BMX Frame
  • Fork


  • Bearing race
  • Bearing
  • Top Bearing
  • Top Cap
  • Spacer
  • Gyro Piece
  • Top Gyro Plate

Stem, handlebars and seat

  • Stem
  • Handle Bars
  • Stem Bolt
  • Seat & Seat Post
  • Seat clamp
  • Micro Adjust (for seat)

Bearings and Axle

  • Bearings x2
  • Axel
  • Washers x2
  • Axel Nuts x2


  • Crank Bearing Spacers
  • Cranks
  • Sprockets
  • Crank Arm
  • Crank Spacers x2

Pedals and Sprockets

  • Bolts for Pedals x2
  • Sprocket Bolt
  • Complete wheel x2
  • Socket pegs (optional)
  • Primo Jewels x2
  • Washer x2
  • Socket x2
  • Back Sprocket

Chain and Brakes

  • Chain
  • Chain Tensioners x2
  • Primo Jewels or Axel Nuts x2
  • Washer x2
  • Brake lever x1/2
  • Brake arms x2
  • Brake Cable
  • Tri-Flow

More optional tools

  • Grease
  • A tool kit
  • Old rags
  • Bike stand

How to choose bike parts

If this is your first time building a bike, you might be feeling overwhelmed at how many BMX parts there are and how you go about choosing what type and material, as well as the price.

A man jumping in the air on his BMX bike at sunset

BMX bike frame

Arguably the bike frame is the most important part of the bike, like the skeleton of the whole thing. It’s also the biggest part of the bike.

BMX bikes come in a variety of types of geometry and size, since this can directly impact the bike’s performance. With BMX bikes, you need to decide if you’re building a freestyle BMX or a race BMX, these two main types have different geometries.

When it comes to the frame, you need to take into account the angle of the head tube and seat tube, as well as the top tube length, standover height, chainstay length and bottom bracket height. Depending on your size and preference. and if you will be doing street, ramps, trails or flatland. The angles of these various points as well as the frame weight and material can impact this too.

Frame material options are aluminum, Chromoly, hi-ten steel and carbon fiber. For race BMX you need to go for speed, so lightweight options like aluminum (cheaper) and carbon fiber (strong and more expensive). If you will be doing freestyle and jumps, then you need the strength to go for steel like Chromoly (more expensive) and Hi ten steel (cheaper).

BMX Fork

The fork is very much linked to the, as it is what takes most of the shock from landings and jumps. You can choose to have a fork with Investment Cast dropouts, offset, taper and butting of the tubing, heat treating as well. You can also make the fork of a stronger material to the rest for the bike to save on money.

BMX Stem

The stem will affect weight distribution of the bike, and this is important as it changes depending on if you’re doing BMX racing or BMX freestyling. You’ll need to consider if you want top load, front load, or a drop-down stem. You can have it solid and strong, or lighter to pick up speed.

The reach rise and stack height can also change the feel of the bike overall, Many people like a top load stem with a taller set of bars. You’ll also need to consider your height and arm length and try out different styles to see what you prefer. It’s best to avoid a stem with too many cutouts and machining, since you will be putting a lot of weight and pressure onto a BMX stem so they need to be sturdy.

A close-up of a bicycle\'s front set and frame

BMX Handlebars

Bike handlebars are a good starting point if you’ve never done any DIY. Replacing BMX bike handlebars is a fun option since you can play around with size, geometry, colors, and features. They come in a two-piece or a four-piece.

BMX Headset

A sealed integrated head tube with a sealed integrated headset can make all the difference when it comes to upgrading your bike. You can have a standard size headtube with headset cups that need to be pressed in and loose ball bearings. BMX bikes often have an integrated head tube and headset.

The good news is it’s easy to install and the sealed bearings will usually last a long time when you maintain them. You will find there are different styles of dust caps that can reduce spacers or look aesthetic.

BMX Bike Pedals

Now here comes the fun part. Swicthing up your pedals for a different shape, grip and color can be an easy way to customize your bike without committing to changing a bigger part. BMX pedals come in a range of materials such as plastic/polycarbonate (PC), nylon blend, or metal such as 6065 or 7075 aluminum. You can also get sealed vs unsealed pedals and different types of bearings. Plastic is of course the least expensive as they wear down faster, but hurt less when you hit your shins on them! Usually, plastic will have unsealed bearings or bushings to make them cheaper.

The best option for grip is metal pedals. They also are more durable and hard wearing. Some come with replaceable pins so you won’t need to replace the whole pedal. You can also choose unsealed bearing which is least expensive, or sealed bearings.

For the best of both go for plastic pedals since they’re lighter and cheaper, with replaceable metal pins to get them to last longer.

A man flying through the air on his BMX bicycle

BMX Bike Grips and Pegs

If you have a BMX bike and you haven’t thought about replacing the grips…then you’re missing out. BMX grips come in a range of styles, mainly flange or flangeless, as well as design, length, and rubber options, not to mention colors. You can have metal pegs of aluminum, or plastic pegs with a steel core with nylon composite sleeves.

BMX Seat and Seatpost

There are mainly four categories of seats- pivotal, tripod, railed and combo. For pivotal, you can have a regular version with a bolt that goes through the top, or stealth that has the bolt in the bottom for a sleeker look. Pivotal has better adjustability due to multiple teeth, so you can angle it as you wish. Tripod is more simple and lightweight, with only a small bolt and two angles to position. Combo are seats with the seat post in one, with only one angle. Railed seats are less common, as they have more weight but offer the most adjustability. Seats can also be slim, mid, or fat with padding, as well as a range of colors and styles.

A close-up of a front derailleur, chain, and chain rings

BMX Crank

Usually, BMX bikes have a 3 piece design of two crank arms and a spindle. You’ll get cranks with spindles in 19mm, 22mm, and 24mm, cranks with larger spindles offering more strength for street riding. With a 48 spine spindle, you can use a spline drive BMX sprocket to reduce bolts.

BMX Bike Tires

If you do street riding, then a smoother tread pattern with a wider width and higher TPI. Ramp riders will love smooth but narrower tires and higher PSI. For trail riding than tires with more tread and width. Width ranges from 1.95″ to 2.40″ PSI ratings from 60-120 on the wheel.

BMX Bike Hub and Rims

The bike hub is customizable too, you can have male or female axles hub made from Chromoly, aluminum, and titanium metal axles, bolts, washers, cones, and drivers as well as color options. There are double wall rims or single wall rims, or wider rims with shorter sidewalls, or a narrow rim with taller sidewalls.

Final Thoughts

Rather than buying a complete bike from the local bike shop, try your hand at building your own, from installing the rear wheel to pivotal seats, you’ll be in charge of each and every bike part. You’ll be able to decide if you want less rolling resistance, pedal backwards, or if you have front brakes or not.

A complete BMX will also have pegs for stunt tricks. If your current bike isn’t cutting it, building your own is the way to go. Plus, the price of assembling the bike is in your hands since you can decide if you’re going to customize it one piece at a time or build it from scratch.

True, it’s a lot easier purchasing a bike at the shop, but all riders can learn a lot from putting their DIY skills to use.

Whether you use videos on a site like youtube or google it, building your complete BMX bike is worth it.

Photo of author


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