What Parts Do You Need To Build A Mountain Bike? A Complete List

You might have considered building a mountain bike on your own. There are some huge benefits to building your own bike. You can purchase the exact components and features that optimize your ride. You can reduce the weight of the bike, add custom features, change the seat style to create a better fit, the list goes on and on. Building your own bike can be extremely satisfying but before you start you should have a full understanding of all the mountain bike parts you’ll need. In this post we’ll discuss the complete list in detail.

What Parts Do You Need To Build A Mountain Bike?

  • Mountain Bike Frame
  • Seatpost
  • Seatpost Clamp
  • Saddle
  • Mountain Bike Fork (Rigid or Suspension)
  • Bearing and Cups for the Seat Tube
  • Crank Set and Bearings
  • Through Axle
  • Front Brakes
  • Rear Brakes
  • Rotars
  • Front & Rear Wheel
  • Mountain Bike Stem
  • Mountain Bike Handlebars
  • Mountain Bike Grips
  • Levers
  • Derailleur, Derailleur Mounts & Shifters

Once you purchase all of the parts above you are ready to rock and roll and start building your mountain bike. But before you do be sure to read on for some special tips and instructions regarding each of these parts. One of the most important things to consider when building a bike from scratch is sizing and making sure all the parts play nice together. We’ll discuss this in detail below.

List of Mountain Bike Parts In Detail

Mountain Bike Frame

Bike frames come a variety of styles and sizes. It’s important to try ride different bikes before you purchase your frame so you get a nice fit. Some frames are stiffer than others and that’s another thing to evaluate before you purchase. A bike stand makes assembling the mountain bike much easier.


The next part we’ll look at is the seatpost. This is the long tube that inserts into the the seat tube. The most important thing here is to make sure your measurements are correct. Even being off a little bit can cause an issue with the assembly. So take your time and make you order a seat post that has a diameter that fits snugly inside your seat tube. Seat posts have different offsets which will change the sizing of your bike.

Seatpost Clamp

The seat post clamp is a pretty simple part. It’s simply going to secure the seat post to the seat tube. Again be sure to match up the diameter with your frame and and post.


The saddle must fit your butt. This is one of the easiest things to customize on a mountain bike. Having a comfortable saddle is the difference between a ride from hell and a dream ride. Take your time and examine which saddle feels comfortable on your sit bones. Make sure your seat posts matches your saddle.

Mountain Bike Fork (You can pick rigid or suspension)

The fork will go into the head tube. Most older bikes had straight head tubes. More modern bikes have a tapered head tubes. Once again measure those diameters to the millimeter to make sure you have the right sizes for your bearings. With those tapered tubes be sure to measure the top area of the head tube diameter. As it tapers the size will change. Once you have your measurements you can order those bearings.

When you are buying your new fork the steering tube (part of the fork) will be way longer that your head tube. You’ll need to cut it down to fit your other parts. If you have a used fork it will have already been cut.

You’ll also need to start thinking about your wheel size when you are evaluating forks. You need to make sure you have tire clearance once those wheels go on.

Lastly you’ll need to see if you have a through axle or quick release. Also make sure the fork will accommodate the type of brakes you’ll be installing.

Bearing and Cups for the Seat Tube

These will be inserted into both sides of the head tube. The cups normally come with the bearings. Once the bearings are installed you are ready to add the fork.

Crank Set & Bearings

It’s time to check out the crank sets. Once again you’ll want to measure out the diameters. You’ll want to make sure the crank set fits with your mountain bikes frame and more specifically the bottom bracket shell. The crank set should fit comfortably.

Through Axle

You’ll want to make sure your through axle fits your mountain bike frames. Check to see which side has threads so you’ll know which side to insert.

Front Breaks

This gets a little tricky. These components have different standards and you’ll need to make sure all of these parts play nice together. The front break caliper needs to mount onto the fork.

Rear Breaks

Same story with the rear breaks. Look at your frame and make the measurements you have match up with the tire to make it a perfect fit.


The larger the rotar the more speed and aggressive riding you can do. The standard for mountain bikes is 160 mm in the rear and 180 mm in the front.

Front Wheel & Rear Wheel

You can breakdown and build each of your wheels with custom parts. For this posts we are assuming you have a fully assembled wheel that’s ready to mount onto a bike. You need to make sure you match the holes in the rim with the number of spokes. The main components of the wheel are:

  • Tires – The part of the bike that actually touches the ground.
  • Tubes – You can also go tubeless if you’d like.
  • Rim – The rim holds it all together and the wheel connects to it.
  • Nipples – The nipples connect the spokes to the rim.
  • Spokes – They extend from the hub to the nipples.
  • Hub – The center portion of the wheel where the spokes connect.
  • Rim Tape – You’ll need some rim tape to see the tire to the rim if you are going tubeless.

Mountain Bike Stem

The stem must match the fork and the handlebars. They come in a variety of sizes so you’ll need to dig in and find out exact matches for all these parts.

Mountain Bike Handlebars

There are different styles of mountain bike handlebars. You’ll want to try out all of the styles before purchasing any. Your size, style of riding and other factors will impact the feel of your handle bars.

Mountain Bike Grips

This is all about comfort color. You shouldn’t have too much trouble with this as most grips will fit any handle bars. Just be aware that when you install the break levers they need to be set up so as not to be touching the grips or preventing grips from being installed all the way onto the handlebars.


You’ll need to mount the shifting lever and the breaking levers. Be sure to take your time with this to make sure you grips are put together with the levers in a way that is comfortable and easy to manipulate on the bike.

Derailleur, Derailleur Mounts& Shifters

Of all the mountain bike parts we’ve discussed so far the derailleurs and shifters can be a bit tricky. Many brands simply don’t play nice with each other. It’s an easier decision if you with the same brand for these components. If you are set on getting different brands that’s ok but do your due diligence to make sure the work together. Ask the manufacturers and they should be able to advise on this.

Related Questions

Will you need additional parts and components for a full suspension mountain bike? Yes you will need some additional parts if you are going to build a full suspension bike. The part list above is based on a rigid bike build.

Is it cheaper to build your own bike or to purchase a bike that is already built? This will depend entirely on the types of components you are installing. Just like bikes each component has a wide pricing range. If you are just starting out it would be best to purchase a whole bike. As you learn what feature you’d like to change you can replace them. Once you understand all the components of your mountain bike inside and out you can do a build from scratch with all the features you desire.

Mike Rausa

I'm a 42 year old married father of 3 that fell in love with mountain biking late in life. Mountain biking quickly became my go to fitness activity. I created this blog to help beginners to advanced riders with tips and strategies to improve your riding experience. More About Me... https://mountainbikinghq.com/mike-rausa

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