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!

 

[martinvb]

Back in Action: Head Tube Manufacturing and Metal Parts in Progress​

Hey everyone! After taking a short break in January to catch up on other projects, I’m back with some exciting progress on the eBike build. Even though I haven’t posted in a while, work has been moving forward, especially in refining the manufacturing process for the head tube plug and launching the milling of key metallic parts for the motor mount and rear triangle.

Refining the Head Tube Manufacturing Process​

The original plan was to use resin 3D-printed molds for the head tube, but after running initial tests, I found that they weren’t dimensionally accurate enough for this application. Precision is critical in this area, so I decided to shift to a prepreg carbon fiber mold approach. This involves creating high-accuracy master molds, which will allow me to produce carbon fiber components within tight tolerances.

Current Focus & Next Steps​

For now, my priority is ensuring the head tube manufacturing process is fully dialed in before moving forward and finalizing other designs. Once I’m confident in the results, I’ll shift my focus to closing out the remaining designs and continuing with the next manufacturing steps.

I’ll keep you updated as things progress, and I’ll be sharing more details soon. Stay tuned!

 

[martinvb]

Project Update: Progress on the eBike Design and Assembly​

The eBike development is moving forward, and at this stage, I’ve been refining several details in the CAD design. Some key components are now finalized, while others are in the final stages of adjustment before moving on to manufacturing.

Motor Mount and Suspension Rocker​

One of the most significant updates is the completion of the motor mount design. With this finalized, I can now focus on the suspension rocker, one of the most interesting components of the frame. I’m exploring different approaches to optimize its design, and in the next post, I’ll share more details about its development.

Mounting System Optimization and Cost Reduction​

To make the manufacturing process more efficient, I’ve decided to unify the mounting system of the rocker and the chainstay. This helps reduce costs and simplifies assembly without affecting functionality.

Head Tube Molds and Test Assembly​

I’ve also made progress on the head tube molds. The master models are now ready, so I’ll soon begin fabricating the final molds.

Additionally, all the carbon fiber tubes have been manufactured, marking a significant milestone for the project. To ensure that everything fits correctly before the final assembly, I’ve 3D-printed key components using filament and conducted a test assembly. So far, the results have been very positive, giving me confidence to proceed with the final manufacturing steps.

What’s Next​

In the coming days, I’ll continue working on the rocker and testing the virtual assembly of the components. With each step, the eBike is taking shape, and I’ll soon be sharing more concrete updates on the manufacturing process. Stay tuned for the next update!

 

[Suns_PSD]

You have lots of skills. So many skills that there is no way in Hell these 100s of hours, to build this bike that will no resale, is cheaper than just buying a used mass produced e-bike.

Fun project though!

 

[martinvb]

You have lots of skills. So many skills that there is no way in Hell these 100s of hours, to build this bike that will no resale, is cheaper than just buying a used mass produced e-bike.

Fun project though!

I get what you're saying, but since I'm not paying myself for the time spent, in a way, it does feel cheaper. Plus, when you buy something off the shelf, you're stuck with the geometries that companies decide on, whereas designing from scratch gives me complete freedom.

But more than anything, I genuinely enjoy the process of creating just as much as using the final product. For me, it's as much a hobby as riding the bike itself. It’s not for everyone, but I find it incredibly rewarding.

P.S. I’ll probably end up spending as much or even more since I’m going for top-tier components and some cutting-edge battery tech… so yeah, that one's on me!

 

[Plummet]

That's a huge effort. Great work.
Now my only negative feedback is that the rear chain and seat stays look too small on OD. In Hindsight making them bigger od might have been better.

 

[Plummet]

You have lots of skills. So many skills that there is no way in Hell these 100s of hours, to build this bike that will no resale, is cheaper than just buying a used mass produced e-bike.

Fun project though!

This is not about cost savings, its about self-actualisation.

 

[Suns_PSD]

I get what you're saying, but since I'm not paying myself for the time spent, in a way, it does feel cheaper. Plus, when you buy something off the shelf, you're stuck with the geometries that companies decide on, whereas designing from scratch gives me complete freedom.

But more than anything, I genuinely enjoy the process of creating just as much as using the final product. For me, it's as much a hobby as riding the bike itself. It’s not for everyone, but I find it incredibly rewarding.

P.S. I’ll probably end up spending as much or even more since I’m going for top-tier components and some cutting-edge battery tech… so yeah, that one's on me!

As long as you admit that, and don't claim it's to save money.

About 1x every year on mtbr.com someone will come on there and explain how they have absolutely NO money, and they have a budget of $150, for example, to spend on a mountain bike. They will then proceed to spend 200 hours trying to procure their $150 MTB. Meanwhile spending that much time as an employee at McDonalds would have yielded them a $3.5K bike. And I'm quite certain with your skills, you don't get paid McDonald's wages.

Building your own bike for the thrill of it, dope as hell! However, an engineer (or whatever it is that you do) manufacturing a bike to, 'save money' = dumbass. Because time is your most valuable asset.

I'm going to be up front with you, these manufacturers are not idiots and have figured out a lot of stuff over the years. It's unlikley that your bike will perform as well, or be as reliable, as even a used entry level e-bike. That's just the honest truth. Not because you aren't smart, but because you haven't spent the last 2 decades building bikes.

GL!

 

[Plummet]

As long as you admit that, and don't claim it's to save money.

About 1x every year on mtbr.com someone will come on there and explain how they have absolutely NO money, and they have a budget of $150, for example, to spend on a mountain bike. They will then proceed to spend 200 hours trying to procure their $150 MTB. Meanwhile spending that much time as an employee at McDonalds would have yielded them a $3.5K bike. And I'm quite certain with your skills, you don't get paid McDonald's wages.

Building your own bike for the thrill of it, dope as hell! However, an engineer (or whatever it is that you do) manufacturing a bike to, 'save money' = dumbass. Because time is your most valuable asset.

I'm going to be up front with you, these manufacturers are not idiots and have figured out a lot of stuff over the years. It's unlikley that your bike will perform as well, or be as reliable, as even a used entry level e-bike. That's just the honest truth. Not because you aren't smart, but because you haven't spent the last 2 decades building bikes.

GL!

The world is quite that black and white is it. Joe punter with an 8-5 job might not be able to moonlight for extra hours for a variety of reasons. But they can sneak an hour here and an hour there to design and build something. Plus if its a hobby and the act of designing and building is part of the fun then allocating that hourly rate is kind of moot.

As an example you could be working an additional hour rather than replying on internet forums. But you are doing it for relaxation/enjoyment.

The actual physical cost is likely to be less than buying an off the shelf e-bike. The other added benefits if op is a mech engineer or designer for a day job then he has a project completed and can use to showcase his abilities to lead to better employment. Or if he wants to dive into the bike manufacturing industry then he has a working prototype for his first design.....

The world is a continuum of shades of grey.......

 

[martinvb]

The world is quite that black and white is it. Joe punter with an 8-5 job might not be able to moonlight for extra hours for a variety of reasons. But they can sneak an hour here and an hour there to design and build something. Plus if its a hobby and the act of designing and building is part of the fun then allocating that hourly rate is kind of moot.

As an example you could be working an additional hour rather than replying on internet forums. But you are doing it for relaxation/enjoyment.

The actual physical cost is likely to be less than buying an off the shelf e-bike. The other added benefits if op is a mech engineer or designer for a day job then he has a project completed and can use to showcase his abilities to lead to better employment. Or if he wants to dive into the bike manufacturing industry then he has a working prototype for his first design.....

The world is a continuum of shades of grey.......

I completely agree with you. As you imagined, my background is in industrial design and product development engineering. I work in the R&D department of a company specializing in carbon fiber structures for the aerospace and motorsport industries. I’m lucky that my job aligns perfectly with my passion—though to most people, it might sound crazy that after a full day at work, I come home and do pretty much the same thing for fun!

Regarding costs, as I mentioned earlier, this definitely isn’t a cheaper alternative. Right now, I’m estimating around $3,000 just for the frame, including tooling like molds and bonding fixtures. And that’s before even factoring in components and the motor… I don’t even want to think about that part!

That said, my case is a bit different since I’m pushing for a technically challenging frame. If the goal were simply to save money on an eMTB frameset, it would definitely be possible—but that’s not what this build is about. For me, it’s more about learning, experimenting with different technologies, and exploring new manufacturing methods.

As for employment, I’m definitely adding this project to my portfolio, and who knows what opportunities it might bring in the future? In fact, there are already some components where I see potential for commercialization—like cranksets (spoiler alert!). I’ve been working on something special, and they’ve already passed stress testing with flying colors at an insanely low weight—way below anything mass-produced.

 

[martinvb]

That's a huge effort. Great work.
Now my only negative feedback is that the rear chain and seat stays look too small on OD. In Hindsight making them bigger od might have been better.

Yeah, this was purely for cosmetic reasons, but I did increase the thickness to compensate for the smaller outer diameter. Definitely taking a slight weight penalty, but mechanically speaking, the frame can handle up to 6 tons of load in the cranks before anything gives out—so the real weak point is actually the motor bolts to the frame.

 

[Plummet]

I completely agree with you. As you imagined, my background is in industrial design and product development engineering. I work in the R&D department of a company specializing in carbon fiber structures for the aerospace and motorsport industries. I’m lucky that my job aligns perfectly with my passion—though to most people, it might sound crazy that after a full day at work, I come home and do pretty much the same thing for fun!

Regarding costs, as I mentioned earlier, this definitely isn’t a cheaper alternative. Right now, I’m estimating around $3,000 just for the frame, including tooling like molds and bonding fixtures. And that’s before even factoring in components and the motor… I don’t even want to think about that part!

That said, my case is a bit different since I’m pushing for a technically challenging frame. If the goal were simply to save money on an eMTB frameset, it would definitely be possible—but that’s not what this build is about. For me, it’s more about learning, experimenting with different technologies, and exploring new manufacturing methods.

As for employment, I’m definitely adding this project to my portfolio, and who knows what opportunities it might bring in the future? In fact, there are already some components where I see potential for commercialization—like cranksets (spoiler alert!). I’ve been working on something special, and they’ve already passed stress testing with flying colors at an insanely low weight—way below anything mass-produced.

Yeah, this was purely for cosmetic reasons, but I did increase the thickness to compensate for the smaller outer diameter. Definitely taking a slight weight penalty, but mechanically speaking, the frame can handle up to 6 tons of load in the cranks before anything gives out—so the real weak point is actually the motor bolts to the frame.

Awesome.

You can also turn your two passions into a side hustle business as well. Once you have a design dialed i'm sure there'll be guys who want a niche e Bike only a few made in the world machine. One day it might become your full time gig.

I too am in industrial design and have do my own design on the side. In my instance it was developing a vertical bike rack. I know sell them as a side hustle business. Its super cool to design and develop something and then sell it to some other stoked person who loves the product you have dreamt up in your head.

Inventors of fire pits and bike racks | Plummet Industries | Taranaki

Inventors of Artisan fire pits, exceptional bicycle haulage systems Plummet Industries | Taranaki

www.plummetindustries.co.nz