Crafting Your Bike Frame: a Step-by-Step Guide With Our Bamboo Bicycle Frame Build Kit

I successfully built a bamboo bicycle using our Bamboo Bicycle Frame Build Kit. In this project, I not only learned how to utilize the unique properties of bamboo (lightweight yet strong) but also actively participated in the entire construction process. During assembly, I carefully performed miter cuts on the bamboo tubes, applied epoxy resin to ensure stable connections, and reinforced the joints with carbon fiber for added durability.

Once completed, riding the bicycle I crafted with my own hands was an indescribable feeling. Every pedal stroke filled me with immense pride, as if each piece of bamboo was telling the story of my effort and creativity. The final product is not just a testament to my hard work; it embodies the fusion of sustainability and craftsmanship.

However, it’s important to emphasize that completing this project requires patience, and undeniably, it comes with a bit of a challenge. Of course, to create a perfect bike frame, you may need to think through many details. We welcome you to join the discussion!

Kit Components

1. Frame Materials
2. Bamboo: Includes top tube, seat tube, down tube, chainstays, and seatstays.
3. Aluminum connectors: Head tube, bottom bracket shell, dropouts, and seat tube connectors.
4. Blueprints
5. 1:1 scale blueprints based on height, allowing you to choose the appropriate frame size.
6. Frame Assembly Jigs
7. Jigs for positioning and supporting the frame during assembly: head tube (pair), seat tube (one), bottom bracket (one), and dropouts (one).
8. Frame Fixation and Reinforcement Materials
9. Epoxy Resin (80ML) with curing agent (25ML) for initial assembly (workable for 1–2 hours, full cure in 24 hours).
10. Fast-curing Epoxy Resin (25ML): Workable for 5–10 minutes, full cure in 24 hours.
11. Carbon Fiber
12. Bidirectional carbon fiber cloth: For reinforcing major joints.
13. Unidirectional carbon fiber cloth: For reinforcing the dropout connections.
14. Carbon fiber thread: To wrap the carbon fiber cloth around the joints, ensuring a secure fit.
15. Other Tools
16. Brushes, mixing sticks, wood files, scissors, and more.

About Build bamboo bicycle frame kit

Begin by assembling the jigs that will support the bamboo frame during the build process. Using screws, secure the square wood blocks to the round base, and position the jigs in the following order:

1. Head tube: one pair
2. Seat tube: one
3. Bottom bracket: one
4. Dropouts: one (Ensure that the dropout jig is perfectly vertical using a right-angle square).

Next, measure the distance between the dropouts based on your chosen bike type. Common measurements are:

1. Fixed gear: 110mm
2. Road bike: 130mm
3. Mountain bike: 135mm

Mark these positions on the dropout jig. Finally, place the head tube, bottom bracket, and dropouts into their respective jigs according to the blueprint dimensions. Please note that the bottom bracket shell has distinct left and right sides (The right side of the bottom bracket has a reverse (counterclockwise) thread. You can place a ballpoint pen on the thread and rotate it clockwise. If the pen can rotate out, then this side is the right side of the bottom bracket. If it doesn’t, then it’s the left side).

miter cut and sand the bamboo tubes at an angle to ensure they fit snugly with the aluminum connectors like the bottom bracket, head tube, and dropouts. It's recommended to start with the seat tube, followed by the down tube, top tube, chainstays, and seatstays.

If you have professional tools for angled cuts, the process will be easier. However, even without specialized equipment, you can still achieve good results—perfect seamless joints are not essential since carbon fiber will be used for reinforcement.

After miter cutting, sand the areas to be joined, including the bamboo joints and aluminum connectors, such as the head tube, seat tube, and dropouts. Remove the smooth bamboo skin and make the surfaces rougher for better adhesion. You can also use a handsaw to cut some grooves into the bamboo for additional grip when wrapping the carbon fiber.

Tip: Naturally grown bamboo is not always perfectly round or straight, so when making miter cuts, skillfully use the curved sections of the bamboo to achieve an aerodynamic effect.

Use fast-curing epoxy resin to temporarily fix the seat tube, down tube, top tube, chainstays, and seat stays in place. Work with the assembly supports, applying small amounts of resin mixed with bamboo dust at the joints for a stronger bond. Hold each joint in place for about 10 minutes to allow the resin to partially cure before proceeding to the next one. Once all the tubes are in place, allow the assembly to cure fully for 24 hours.

Before fixing each bamboo piece, it's best to repeatedly test whether the position is accurate and suitable.If necessary, you can make slight adjustments or sand the bamboo.

(Approximate time: 4 hours; you can divide this into two or four sessions)

Method 1: Multi-layer Carbon Fiber Cloth Wrapping

This method involves wrapping multiple layers of carbon fiber cloth around the joint to provide additional strength and rigidity. Here's the process:

First, cut the carbon fiber cloth into appropriately sized pieces. Then, apply epoxy resin to each layer and wrap them around the joint one by one. Make sure each layer adheres well to the previous one, using a brush or roller to eliminate any air bubbles or gaps. You can add as many layers as needed to ensure sufficient strength.

Reinforce the joints using natural fibers or synthetic carbon fiber. Natural fibers require more epoxy and careful sanding, while carbon fiber uses less resin and may not require as much finishing work if applied correctly.

Start reinforcing the easier areas first, such as the dropouts, followed by the head tube, seat tube, and bottom bracket shell.

1. Dropout Reinforcement: Wrap the dropouts with unidirectional carbon fiber cloth, cut into four segments. Begin by applying a layer of epoxy resin to the bamboo and the carbon fiber, then wrap the fiber tightly around the joint. Use carbon fiber strands to further tighten the wrapping. For a smoother finish, wrap the assembly with the reverse side of electrical tape.
2. Head Tube Reinforcement: Cut strips of bidirectional carbon fiber cloth (about 4 cm wide) and an additional piece large enough to cover the entire head tube area. Apply epoxy resin to the bamboo and carbon fiber and wrap the strips around the connection points, using the larger piece to cover any stray fibers for a cleaner finish. Apply at least four layers of carbon fiber for maximum strength.
3. Seat Tube Reinforcement: Reinforce the seat tube in the same way as the head tube, using two large pieces of carbon fiber cloth for additional strength on both sides of the joint. Again, apply at least four layers of carbon fiber.
4. Bottom Bracket Shell Reinforcement: This is the most challenging joint to reinforce due to space constraints. Use carbon fiber strips to carefully wrap around the joints, applying more layers (at least five) for added strength, as this area supports the most weight.

Allow the frame to cure for 24 hours before moving to the next step. Once fully cured, sand down any raised carbon fibers for a smoother finish.

Tips:

1. Patience is key during the reinforcement stage, especially around tight corners and small spaces.
2. For smoother transitions between bamboo tubes and aluminum connectors, aim for an even surface before wrapping with carbon fiber to achieve a more polished look.
3. When applying carbon fiber, make sure to press down firmly to eliminate air pockets, ensuring a solid bond.

Method 2: Using Chopped Carbon Fiber for Joint Reinforcement

This method involves applying chopped carbon fiber mixed with epoxy resin at the joints, followed by wrapping with carbon fiber cloth. It is simpler and easier to execute than applying multiple layers of carbon fiber cloth alone. Here's how you can do it:

You can either purchase chopped carbon fiber or cut carbon fiber cloth into small strands of about 10mm to 20mm in length. Mix these chopped fibers evenly with epoxy resin and apply them uniformly to the joints, ensuring even thickness. Afterward, wrap the area with carbon fiber cloth for added structural integrity.

My Opinion on This Method: This approach is highly practical, especially for those working on custom or home-based projects. By using chopped carbon fiber, you simplify the process of filling complex or uneven surfaces, ensuring that the joint is reinforced properly without the difficulty of managing multiple layers of cloth. Additionally, the final wrap with carbon fiber cloth not only provides extra strength but also enhances the aesthetic finish. This method is especially useful when working with intricate geometries or areas requiring precise reinforcement.

After the epoxy resin has fully cured, you can do some light sanding, and if you like, you can also paint on it.

Then purchase the appropriate accessories for assembly.

Bamboo Bicycle Maintenance

To keep your bamboo bicycle in optimal condition, follow these maintenance tips:

1. Regular Inspections: Periodically check for any signs of wear or damage to the bamboo frame, especially at connection points.
2. Cleaning: Use a soft cloth to wipe down the bamboo surface regularly. Avoid harsh chemicals; instead, use mild soap and water if needed.
3. Reapply Finish: If your bamboo is not coated with a protective finish, consider applying a natural oil or wax every few months to enhance durability and protect against moisture.
4. Tightening Connections: After the first few rides, check and tighten any screws or bolts to ensure stability.
5. Storage: Store your bicycle in a dry, cool place away from direct sunlight to prevent the bamboo from warping or fading.

Congratulations on successfully completing your first bamboo bicycle! If you're still interested, you can now continue to challenge yourself with a fat bike and a tandem bicycle and a tall bike etc.