Skip to Content

What are BMX Frames Made Out of? (Materials Explained)

A BMX bike is usually constructed with maximum strength but minimum mass. The lightweight yet robust design is only possible if the correct material frame has been used.

The material of the BMX frame is one of the most integral factors that determine how you would feel when riding the bike. Moreover, it also determines how sturdy and durable the bike will be.

So, what are the materials that are used to construct your riding partner? It is also pivotal to know whether one material is best or there are a few that make long lasting and high-quality BMX bikes.

What are BMX frames made out of?

The most common material used to make BMX frames is an alloy metal called Chromoly steel Another frequently used material in BMX frame is 1020 steel, and the mixture of both these materials is also used. Other metals like aluminum, titanium, and carbon fiber are used to make BMX frames, as well.

The material used to build BMX frames should be should produce an end product that is lightweight, but also stiff and delivers the utmost strength.

Over the years, a wide range of materials has been used to make such frames. While some are more lightweight than others, few make BMX bikes that are comparatively more expensive.

Here are 6 commonly used materials for BMX frames:

Chromoly Steel:

If you look into the BMX frames and materials, you’ll find that a lot of the frames are build from an alloy material called Chromoly, which can also be referred to as 4230 metal.

The alloy is comprised of chromium and molybdenum. Chromoly Steel is one of the most lightweight framings available in BMX bikes, combined with an incredible weight strength ratio.

Carbon Steel:

BMX bikes that are usually designed for beginners or kids, are usually made with carbon steel. This material is high tensile steel, which usually lasts for years to come.

However, carbon steel is not used for adult BMX frames because they are not as light in weight as other materials.

1020 Steel:

Since steel comes in many grades, one affordable alternative is 1020 steel used to make BMX frames. Although this steel does not produce a BMX bike with great strength to weight ratio, the material is used to make the bike cheaper, as well as more available.

Oftentimes, BMX frames can also be made with a combination of Chromoly Steel and 1020 steel, which makes the overall end bike durable, lightweight but also helps to cut costs.

Carbon Fiber:

Heaps of graphite layer on one another is attached with an adhesive to make carbon fiber.

This material is usually used in ariel vehicles because its ability to make frames are minimized in heaviness but delivers maximum strength, combining malleability and stiffness.

However, they are prone to cracking and are quite expensive.


Aluminum is a very popular metal when it comes to making BMX frames, due to its ability to construct frames that are long-lasting and lightweight.

As it is much less dense than steel, a lot of material is required to achieve the desired forte and weight.


Like aluminum, titanium produces BMX frames that are rust and corrosion resistant, which means such frames are highly durable.

Although titanium is not as stiff as steel, it does make frames that quite light in weight.

What is the best material for a BMX frame?

BMX bikes are mainly used for off-road riding and it the bike of choice when it comes to performing stunts and aerial acts. Such a bike needs to be made of materials that can produce incredibly lightweight, yet stiff framing.

For this, a steel frame is a great choice. However, since steel or any other metal is not used in its purest form, a steel allows called Chromium steel is one of the best materials for BMX frames.

Although such a framing can result in expensive bikes, the finished product is usually highly durable and low in weight. Moreover, Chromoly steel BMX bike frames have impeccable weight and strength ratio, making them ideal for fast racing, bike jumping, and stunts.

Another cheap, yet durable material considered to be great for BMX frames is aluminum.

Although aluminum-framed bikes can give you a rough-riding experience, there is no second-guessing their ability to deliver frames that are strong and stiff, while having a weight low enough as desired by BMX bike riders.

How to make BMX frame?

  • Step 1: Buy a suitably sized tube, depending on your height. If your height is more than 5 feet 6 inches, opt for a frame size of 20 to 21 inches. If you are any shorter than 5 feet 3 inches, an 18 to 19 inches tube frame will be appropriate.
  • Step 2: Purchase front bars and stems, followed by a suitable headset. The head tube must be compatible in size with the headset.
  • Step 3: Thicken the joining or stress points on the tube so that the strength to weight ratio is adjusted.
  • Step 4: Next, either hand wields or machine wield the tubes into the bike frame. Tig welding is a difficult job and needs years of experience to perform properly.
  • Step 5: Wrap the joining points with sturdy and short hoists. This makes the frame attachment stronger
  • Step 6: Paint or clear coat the bike frame in order to make it longer lasting.

Do raw BMX frames rust?

Raw BMX frames that do not have any coating or painting over them will rust quite easily. However, whether your BMX frame will corrode away will largely depend on what material it is made of.

Steel frames, that are not chemically coated on the surface will start to rust within a couple of days, especially if you live in an area with higher humidity levels.  Aluminum or titanium frames are intrinsically rust or corrosion-resistant.

Moreover, if you have a BMX bike that has painted frames, you may notice rusting as soon as some part of the frame has been scraped or scratched.

Rusting in frames occurs when the material of the frames comes in contact with moisture in the air, causing a chemical reaction to start on the frame. This then leads to oxidation of material and hence rusting begins to be visible.

How do I know if my bike is steel or aluminum?

To your eyes, aluminum and steel can look too similar in appearance, and telling them apart is almost impossible. If you want to find out for certain if your bike frame is made of aluminum or steel, there is a simple visual test that can push the confusion aside.

For the test, you’d need a magnet. Take the magnet and place it near the bike frame. If the bike pulls the magnet or sticks to it, surely your bike frame is made of steel.

However, if it does not get attracted, your bike is possibly made of aluminum or other carbon fiber materials. Additionally, if the tube on the bike is cylindrical, your bike is made of steel.

It could also help to know some basic differences between steel and aluminum in general:

  • Aluminum bike rides are rough, while steel frames offer smoother rides
  • Aluminum is brittle while steel does not dent or bend.
  • Aluminum frames are straight gauge as opposed to steel frames which are double butted
  • Aluminum frames have a larger diameter than steel frames.

What steel is used for bike frames?

To made bike frames, an alloy of steel, known as Chromoly steel is commonly used. Chromoly steel is also commonly known as 4130 and is known to be lightweight, as well as, hard-wearing.

Why are bike frames made of Aluminum?

Bike frames have been constructed with aluminum for decades, and one of the primary reasons is their availability and low cost. Aluminum frames are brittle, but they make frames that are fairly decreased in weight and are enduring.

Are aluminum bike frames strong?

Aluminum bike frames in themselves are considerably strong and light but when compared to steel frames, they are not as durable. Steel on the other hand is considered to be resistant to bending or denting, while aluminum can be quite brittle.

Are steel bike frames better than aluminum?

When compared face to face, steel bike frames are considered to be better than aluminum bike frames. This is because steel frames are the most durable materials, and are stiff, strong, and lightweight, making them ideal to be used for BMX frames.

For any bike, including a BMX, the framing is considered to be the backbone of the bike. This means the material used to make BMX frames must be lightweight, stiff, and exceedingly durable. For that, a steel alloy frame can be considered to be the best option. 

Frequently Asked Questions:

Are BMX bikes good for adults?

Can you sit on a BMX bike?

Why are BMX bikes so small?

How much weight can a BMX bike hold?

Does BMX size matter?

Does BMX tire width matter?

Are BMX bikes heavy or light?