Aggressive Long-Travel Enduro eBike Build: From Concept to Trail-Ready

[Freda]

Hey Freda, my initial plan was to go with the M820 motor, but I couldn’t get my hands on one. Luckily, someone here offered me an M510 at a great price, so I decided to go with that .

As for the linkages, if you check my earlier posts, you’ll find the full simulation along with the geometry values that I pulled from Linkage X3. In the CAD, I’ve started working on everything I can before scanning the motor, which is why the motor mount and rear triangle anchor points aren’t included yet.

Thanks for your feedback!

Oh sorry, I did see that post earlier and still forgot.. Yes that looks good, very progressive.

Your battery has 21700 cells? I built a ~500Wh and first opted for 21700 cells but then realised using 18650 cells take about the same amount of space and weight. The benefit being 3P configuration for 18650 to 2P for 21700 cells.

 

[Goff]

I have been thinking of building a intergraded battery in the frame as I wrap the batteries I build in carbon anyway, it means you can reduce weight, it’s stronger and the down tube is sleek.
Obviously the down side if you have a battery or bms problem you have to cut the frame, but I have had no problems with a battery yet and if you know what you are doing you can design it in a way to allow for a cut line to remove the bottom side of the down tube and repair the frame.

I think you should consider a range extender, 500Wh (18650 cells) will be enough, there is so much focus on having a big battery, but the weight penalty is not great, but with a 250Wh range extender you can have that extra range for big ride.

Just something to consider

 

[martinvb]

I have been thinking of building a intergraded battery in the frame as I wrap the batteries I build in carbon anyway, it means you can reduce weight, it’s stronger and the down tube is sleek.
Obviously the down side if you have a battery or bms problem you have to cut the frame, but I have had no problems with a battery yet and if you know what you are doing you can design it in a way to allow for a cut line to remove the bottom side of the down tube and repair the frame.

I think you should consider a range extender, 500Wh (18650 cells) will be enough, there is so much focus on having a big battery, but the weight penalty is not great, but with a 250Wh range extender you can have that extra range for big ride.

Just something to consider

The range extender is something i was already planning on. About the battery it will be an integrated battery with a carbon enclosure but it will be extractable trough the motor mount for serviceability.

 

[Thomas39]

Ciao, con 500 W a 1500 D+ puoi arrivarci solo in modalità eco e su strade lisce. Valuta un 600 W.
se si desidera installare un display sul tubo superiore, la forma rotonda potrebbe rappresentare un problema.

 

[martinvb]

Ciao, con 500 W a 1500 D+ puoi arrivarci solo in modalità eco e su strade lisce. Valuta un 600 W.
se si desidera installare un display sul tubo superiore, la forma rotonda potrebbe rappresentare un problema.

Thanks for the point on the screen. I'm aware of that and my workaround is to not have a screen at all. At the end of the day a simple matrix led for battery stat, 5 leds to indicate assist level and a couple of buttons on the handlebar is all that is needed in my opinion. Also less stuff that can and will break in the case of a fall...
With 530wh in combined use so eco when is not super hard and boost only in super steep areas it should be enough for 1100-1200m+ and if i go on a big ride i will be doing a range extender to clip on the bottle holder.

 

[martinvb]

Hi everyone,

Apologies for the lack of updates this month. I’ve been busy with other projects and couldn’t dedicate as much time to the bike as I wanted.

Today, I’m sharing the current state of the CAD model along with some key design decisions aimed at improving compatibility and ease of repair. For the derailleur hanger, I’ve chosen to use the SRAM UDH (Universal Derailleur Hanger) system. This choice ensures excellent compatibility with most SRAM drivetrains and simplifies component replacements in case of damage, which is especially useful for a bike that’ll be used in challenging conditions.

Motor Update: I recently received the motor, and I’m in the process of 3D scanning it. This step will allow me to reverse-engineer a precise model to integrate it seamlessly into the CAD assembly of the bike. It’ll also help in designing the motor mount accurately, avoiding any interferences and ensuring a perfect fit within the frame.

I’ll be sharing some early renders of the full assembly soon, along with more insights into these design decisions. Thanks for your patience, and stay tuned for more updates!

 

[martinvb]

New Update: Design Progress, Calculations, and Next Steps

The eBike project is moving forward steadily, and I’m excited to share the latest updates! Here's where things stand:

Frame Tubes and Geometry Finalized​

After carefully running calculations and analyzing various options, the frame tubes have been selected and added to the shopping list. The bike’s geometry has also been finalized—no more tweaks or adjustments. This was a big decision since the geometry defines the overall riding experience, but I’m confident it aligns with the aggressive enduro style I envisioned.

Headset Design and Composite Tooling​

The headset section is now frozen as well, and I’ve begun designing the tooling required for composite manufacturing. This part of the project is particularly exciting because it’s a deep dive into custom composite construction techniques. I’ll be dedicating an entire blog post to this component and the tooling process to share all the details and challenges involved.

Topology Optimization in nTop​

One of the most innovative aspects of this build is leveraging topology optimization to create lightweight yet strong components. I’ve started laying out the parts that will undergo this process using nTop. These include:

• Motor mount: Ensuring a perfect balance of strength and weight to securely house the motor.
• Rocker link: A critical element for the suspension system, where optimization can significantly enhance performance.
• Rear dropouts and triangle mount: These are currently under consideration and will depend on the results of structural simulations.

The goal here is to maximize material efficiency while maintaining durability and performance. This approach ties into the overall philosophy of designing a bike that’s both cutting-edge and built to handle tough trails.

Stay tuned for more updates, including a detailed walkthrough of the composite tooling process and insights into how topology optimization is shaping this build. As always, your feedback and questions are welcome—feel free to share your thoughts in the comments!

Preliminary concept model of the tooling and internal bladder.

 

[thaeber]

Great project! Did You ever reach out to DJI and asked for the Avinox System? I think their plan is to offer the motor and battery system to additional OEM, and from weight and power figures both, battery and motor, are a class of its own currently..

 

[martinvb]

Great project! Did You ever reach out to DJI and asked for the Avinox System? I think their plan is to offer the motor and battery system to additional OEM, and from weight and power figures both, battery and motor, are a class of its own currently..

Yes i reached out but got no response, also tried with zf to get the centrix drive and the same outcome unfortunately.

 

[kaaskopf]

just order a bafang m510 motor set for around 750 usd shipped and be done with it.
self servicability

 

[martinvb]

Exciting Progress: Finalizing Components and Starting Manufacturing

The eBike project is reaching an exciting stage as I begin to close the design phases for several critical components. Here’s the latest progress:

Head Tube Refinements​

I’ve made some improvements to the head tube to minimize tolerance stacking, ensuring better alignment and assembly precision. With the tooling now complete, manufacturing for this part has officially started—a major milestone!

Dropouts Ready for Printing​

The rear dropouts are finalized and ready to be produced using selective laser melting (SLM) printing. This process will ensure they’re lightweight and incredibly strong, perfect for the demands of aggressive riding.

Carbon Fiber Motor Mount​

After some deliberation, I’ve decided the motor mount will be constructed from carbon fiber. This will help keep the overall weight down while maintaining the strength needed to secure the motor reliably.

Next Steps​

Here’s what’s coming up next in the design and build process:

• Finalizing the motor mount and bottom protector designs.
• Designing the rocker support and its integration with the frame.
• Performing topology optimization on the rocker to reduce material usage while ensuring structural integrity.
• Completing the shock mount and getting the carbon fiber tubes.

Once these steps are completed, I’ll send all the metallic components (both printed and CNC machined) off for production. Simultaneously, I’ll wrap up the design and fabrication of the battery enclosure and its mount, which will also be made from carbon fiber.

This stage of the project feels incredibly rewarding, as it’s a blend of finalizing designs and seeing them transition into physical components. Stay tuned for more updates, and let me know if you’d like a deep dive into any specific aspect of the process!