[Pedro Neves] has a mid-drive e-bike, but he doesn’t own it — not truly, since he can’t repair the motor unit. For a hacker to be in that position, there are only two options: crack the old one and make it your own, or build your own from scratch. [Pedro] built his own and is open-sourcing it on his website for everyone to play with. Right now, that’s .step files and a BOM, so you’ll need to watch the design/build video on YouTube below to get the full picture.
His choice of a motor from an old battery-powered angle grinder is both thrifty and environmentally friendly, so we approve. His goal of 25 km/h seems like a reasonable speed limit, but may still be too fast for some countries’ regulations— so do check the local rules if you’re going to build this. Making the most of 3D-printed components is also a choice that makes the project more accessible, but don’t worry — the bearing surfaces are all metal. That includes the clutch bearing that will let you pedal home if the battery dies or the motor craps out. Well, unless the printed plastic axle gives up the ghost, but that got replaced with a CNC version, so it’s all good. Unless you’ve got legs like Hercules, it ought to hold.
If that’s not DIY enough, you could always build the motor yourself. This mid-drive is also part of a larger project [Pedro] is working on for a whole cargo bike, as he details in his video, which is a worthy project we’ve seen other examples of before.
Open-Source Mid-Drive E-Bike Motor-Article has too many hyphens! :-)
https://opensource.org/blog/is-open-source-ever-hyphenated
Great project and i can see why you want to do this, but i think we use different definitions of “owning”. Nevertheless curious where this goes.
Ah, so you subscribe to the John Deere definition of ownership.
i see what you did there…
Looks DOA to me due to the puny motor.
Well, as stated, it depends on your definition of ownership. Do you mean the legal meaning that gives you the right to do with something as you please, or is it about open source, open hardware or right to repair?
Most people here install different firmware to overcome the restrictions built in, so they can go faster, have more power, or get support without pedaling. That is of course within their rights, als long as they don’t use their ebike on public roads…
BTW there is apparently a firm doing a right to repair investigation on Bosch https://classlawdc.com/2026/07/13/bosch-ebike-systems-right-to-repair-investigation/
Own it like I own the motor in my car.
Yes, I doubled it’s power.
The factory tune was lame AF.
The legal meaning that gives you the right to do with the item as you please, is the whole idea behind right to repair. Those are not separate ideas. They are EXACTLY the same idea.
If I but something and want to modify it for my own use, I already have that legal right whether or not a corporation wants to recognize it.
I do not need Bosch’s permission to open up a motor I own and plug things into it. Stopping me from doing so deprives me of my rights.
All companies dream of being the purveyor of everything from their own locked-in ecosystem.
Our relationship with them always requires an adversarial mindset. because their only goal makes them an adversary.
Keep seeing this in my recommendations, first on yt, then in all feeds, now here…
Dude made the most ridiculous mid-drive using a generic low-torque brushed motor and some 3d printed parts which will fall apart as soon as that video ends.
We live in times where we have affordable opensource bldc drivers like VESC, and there are VESC-based mid drive kits. There are myriads of DIY designs for vesc head units, which require no more than an esp32 and half-a-brain.
Last time I’ve seen a brushed motor powered transport, was one of those cheap 800w quads for kids. At least those had some torque and speed, comparing to this abomination.
It really triggers me when someone gets praised for reinventing the wheel(sometimes literally) for the 100th time in the worst possible way.
You’re on a maker and hardware hacking site…
Those vesc motors wouldn’t exist if someone didn’t start exact where this guy is now, and refined it to such a good point where people go online and belittle other people’s learning process. And his postings will undoubtedly inspire other people to make their own, and improve theirs, and eventually we get something that’s so much better than the vesc motors that people go online and belittle the people who use vesc.
“Those vesc motors wouldn’t exist if someone didn’t start exact where this guy is now, and refined it to such a good point ”
Im with SilentBogo. “You’re on a maker and hardware hacking site…” The internet exists. Its not the 70s. You dont have to screw around with half assed ideas that have been tried before. You can start with what is known to work and improve from there. Crap like this is just watering down the feeds with more clickbait bullshit for halfwit dipshits. Its bad enough youtube is full of this garbage. HAD should do better.
Dude builds a prototype to mate up with a given attachment specification, based on first principals and off the shelf parts, then makes it open so others can use/learn from it.
If you don’t think that is ‘hacker spirit’ then you don’t belong here.
Clean up your ‘feed’ a bit by leaving so the rest of us don’t have to have our ‘feeds’ filled with your ranting.
Bye
There seems to be plenty of room in your feed for whining so Im sure my rant wont get in the way.
If that guy did even a slightest bit of research, //incoming controversial statement// or asked GPT or whatever, then he’d likely start off with a proper BLDC and a chain drive as a bare minimum.
Also, on a low-end for tinkerers we have a shitton of hacks using cheap gyroboards and EFeru’s FOC firmware, which you can hack together in no time, and tweak/customize to your hearts content. I’ve personally made a couple of heavy RC rovers, a ghetto-escooter, and a small quad using just that. Parts are cheap. I don’t think I paid more than $20 for each gyroboard(used), and you get two 350W motors along with a small battery and a capable STM32 motor controller.
For dude’s project – all it takes is to replace his crap with an e-skateboard motor w/ similar dimensions, add proper sturdy gearbox and buy a $10 generic BLDC controller. Then I wouldn’t have anything to complain about. I’d still think it’s shit, but I would keep my opinion to myself assuming it’s “work in progress”.
That’s the risk of it. More people making more clickbait.
Anyone who serious about building e-bikes would skip right past the random youtube “maker” because that’s mostly just people 3D printing junk to make a video.
If everything you know is a smartphone, every microcontroller looks like a computer to you.
Nice i like this
I haven’t seen anyone using BOM as an acronym in 20 years. Let me regale you with a story about that.
My director and division chief were catching a flight to a conference and one said to the other in the security line at the airport, “Keep your laptop out so we can work on the BOM on the plane.” We were later emailed a directive to immediately switch to using List of Material (LOM).
You don’t work in the companies I have, including aviation. Still used every day.
Both terms are used. They are NOT the same,
BOM: Primary audiences are Manufacturing, purchasing, and production teams
A highly detailed, hierarchical “recipe” for manufacturing a product, including part numbers, sub-assemblies, and supplier information. Used heavily in Enterprise Resource Planning (ERP) and Material Requirements Planning (MRP) to manage inventory, forecast costs, and avoid stockouts.
Primary audiences are Manufacturing, purchasing, and production teams
LOM: Primary audiences are Builders, contractors, or estimators
A simplified, flat document that just lists the basic materials and quantities needed for a specific task without the technical breakdown. Good for estimating bulk needs (like ordering paint, timber, or concrete) but lacks the detailed tracing needed for complex assembly or repairs.
So for the sort of project HAD is generally known for a BOM is more appropriate. Now whether you want to use an EBOM, MBOM, or SBOM is an entirely different matter. But given that your experience for the last 20 years has favored LOM, you probably dont need to worry about that. Just take your list to home depot and build that shed buddy
I know this acronym from software dev.
for real though that plastic is in the load path?? bottom brackets are not a place where you can skimp on tension strength
I was intrigued by the idea of making a mid drive motor unit for an ebike using a 3d printer.
Looking at the results the angle grinder motor wasn’t a good choice mainly because it’s designed to be high revving and would need quite a lot of cogs to get an output speed of around 80rpm peddling speed from a motor spinning at around 25,000 rpm. Gearing on an angle grinder I’d guess would be a reduction of about 3 to 1 for a typical cordless angle grinder with a disc speed of 8000 rpm. So that motor would require a reduction ratio of at least 250 to 1 which would make it very noisy. I’d suggest getting an escooter motor which being bigger and much lower revving could be feed through a planetary gearbox to the pedals. As for the home made clutch. It is subject to too much force to be able to use plastic on that diameter of shaft. I personally would get a rear bike wheel and use the freewheeling sprocket with a chain or toothed pulled to achieve the drive from the electric motor and the sprocket would allow the bike to be peddled without spinning the motor when not using the motor. Also something that would be of a SAFETY concern is the design using plastic to hold the peddle assembly onto the bike frame. If one was to stand up to peddle whilst going up hill and it broke off that could result in a nasty accident.
The entire project is a travesty. Starting off with a 3d-printed bottom bracket spindle is unbelievably stupid– there’s a reason they’re made from hardened steel.
Then there’s the choice of a severely under-powered motor, running what looks like a single-stage reduction gear on the bottom bracket spindle, and he’s wondering why it burnt out!? The guy’s running on vibes and not even running the numbers. At least Tom Stanton does.
A travesty? Really? Like, a devastatingly tragic turn of events? A disaster? An epic and overwhelming affront? You seem so personally invested… did a poorly-made motor-bike hurt you during your formative years? Tell us, how does that make you feel…
For one thing, even the cheapest ebike kits with brushed motors start at 24V 250W. Yet somehow he thinks a puny 12v motor can propel his reverse tricycle, hopefully to 25 km/h? Get real. I’d call what he’s doing “vibe engineering”.
People who engage in hyperbole should be shot.
Right after the grammarians, definition Nazis and patronizing high school psych students get fed through a wood chipper, alive, feet first.
Like something you shouldn’t copy. Just made for the clicks.
Well, it can serve as a negative example.
That tiny brushed motor probably couldn’t propel an RC car to 25km/h much less a bicycle with a heavy sack of human flesh sitting on it.