DIY space frame for an e-bike

People’s Topper e-bike frame. Electric bike crash test

Currently, the world community is experiencing an acute shortage of frames suitable for the construction of an e-bike.

This niche could be filled by Ukrainian production, but unfortunately this is not happening yet. Also, there are a couple of pilot plants, however, the direction of development and the speed of decision-making, as well as the price, are currently depressing.


What was my surprise, okay. In order. A month ago I received a letter from one factory, like we want to make a frame for an electric bike. If you want. do.

Literally two days later they did it. I ate for a long time, but in order not to offend the letter I did not delete, I wrote down all the identified shortcomings point by point.

And after about 8 hours I received photographs of a new frame, already painted, with already corrected flaws. In general, forget all the tales about Japanese robots, about American workaholics and effective management.

I don’t know how it happens, maybe time goes slower in the shop, because the shop is on the space station. But it was done in 8 hours with a lunch break.

And then we changed places, from a lazy critic I turned into a Wishkin. Give, sell, AAAA want

I apologize for some confusion of presentation, I have not yet recovered from the shock. Now I understand how we won the war. For 8 hours a frame, for 36 a tank, for 48 aircraft, for 72 ships. Something like this. (and, as it were, 2 years before repeating success since the beginning of writing this note, the Russian soul is a mystery)

All wishes were taken into account. a motorcycle shock absorber:

Universal head tube for e-bike frame for any fork!

Horizontal slot for motor mounting.

And I’ll tell you what, we won’t stop (stop) Perhaps I understand how to make the perfect e-bike. And perhaps I found those who can do it quickly, with high quality and not expensive.

I already have a bunch of ideas in my head, forced cooling, a titanium pendulum, technological holes, a reinforced pendulum for high speed.

I will keep everyone informed. One feels that this version is just the beginning, but how many will there be? I think this summer I will be able to test my new electric bike, made especially for me, according to my requests, the width I need, weight, strength, etc.

So, the time to publish this material has not yet come, but there are the first results of summer (summer 2014) testing.

After riding with a moderate degree of rigidity, the frame was folded almost in half. All in all, these are two of the two. That is, from two space frames (different manufacturers), it was possible to achieve visible structural changes and thereby prove the fact that any downhill double suspension will be stronger than any space frame (as long as it is).

In the photo there is a test frame, which, when driving the curb at 30 km / h, began to fold, and when driving across the field at 50 km / h, it finally formed into the position of the feet above the head.

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Why is this experiment done? Any mass production must be crash tested. Where to find another moron dummy besides our humble author?

Of course, testing was carried out in a T-shirt, without a helmet. You say don’t believe?

Yes, it was just the day when it was necessary to urgently go to the restaurant, and only the test sample was charged.

And it was hot, I planned to go slowly and carefully. And then he went out onto the track, into the gullies, and on the way back into the field where not every tank will pass.

Never do that. Always use maximum protection!

space, frame, e-bike

Well, it’s okay, half a year of assembly and the second, enhanced version is ready. Which went into series, yeah, exhale, your frames won’t fold;)

We collect and go. But not to break, but to exploit.

And, the usual result in my practice, they worked and scattered. Everyone goes on their own way. Developers design frames, I roll on factory downhill double suspensions.

E-bike Pt2 Frame build

Production is engaged in more profitable projects, and my ideas, as usual, are not massively implemented in metal.

Although the device came out not bad from an aesthetic point of view, it is quite suitable for driving on asphalt and light off-road.

What should those who want a frame do? It is tearful to ask the manufacturer and wait… wait… wait…. or or already now sign up in the queue, in case I decide to share the already assembled device.

Will China help us? At the moment when I write these lines, I hope that the test 3 frames of the Chinese factory assembly are already crossing the border with mexico.

No frills, just a standard, time-tested design, of course, not designed for exorbitant loads.

But according to the Chinese, it is quite calculated at 80 km / h. Only I refuse to break frames at speeds of about a hundred;)

However, the topper on the new serial frame has already been assembled, transported out of town, where it will be presented to the general public after its completion this summer.

Silver metallic color, painted by myself, it came out very well!

Photos will be on the May holidays, possibly a video review!

The concept of the project is a comfortable heavy electric bike, for driving at speeds up to 50 km / h.

To guarantee safety when driving at higher speeds, while, in my opinion, it is impossible on any of the existing spatial frames.

p.s p.s I started this article on April 24, 2014, I decided to publish it remembering about it on April 29, 2015. Coincidence. blogging about e-bikes, building e-bikes, boiling batteries and doing it well.

4 Комментарии и мнения владельцев

I am often asked what is the ideal frame? Like a year has passed, and I never said. But I’m still looking for an answer. But I say right away that I am not ready to put my seal of approval on any mass-produced space frame. Unless with reservations for the speed and height of curbs and curbs.

Why not just copy the frame of light enduro motorcycles? (sorry, if not the topic. Just went to the site)

It’s good that it just bent under you, and did not drive the wheels in different directions. Alexey, be more careful chtol without a crew then).

You can try the roll bar like in the Grapeboy Model S. This is more reliable, the side panels made of plastic or thin sheet metal will give less weight and will be cheaper. And this view will be more beautiful, and the possibility of greater competition in price and quality. Yes, a frame with a roll cage is the most option, I wanted such a bi.

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Drive unit

The position of the drive wheel determines the behavior of the e-bike on the road and off-road, almost like a car. In nature, there are three drive options:


Most e-bikes are based on the hardtail. Its undeniable advantage is its low price and sturdy aluminum or steel frame. One of the main tasks, battery placement, is solved by choosing a hardtail.

The space inside the frame, the “triangle”, provides the ability to install a capacious battery without resorting to other options. For this, the battery is placed in a special bag, which in turn is hung on the top tube. However, on many hardtails there are also trunk mounts, where you can place the main or additional battery.

The disadvantages of a hardtail in terms of electrification are quite obvious. The absence of a rear and sometimes a front shock absorber significantly reduces ride comfort. The speed of an electric bike increases significantly and most of the irregularities are perceived by the rider’s fifth point.

Important! The battery must be well secured to avoid touching the frame and damaging the batteries. To do this, you can wrap the battery in a soft material.

Engine selection

There are different types of motors. The most common ones are:

Rear drive

When installing middrive, the rear wheel remains the leading wheel, like on a regular bike, and you do not need to change the cassette. The front sprocket of the motor pulls the chain, which, depending on the selected gear, switches to the desired rear sprocket.

Rear location of the motor-wheel. the most common. This is due to the usual leading drive for the cyclist. The motor axis is installed in its original place, in the grooves of the dropouts. In this case, you will have to change the cassette to a ratchet, which is caused by the design of the motor housing. A slight decrease in the number of rear sprockets is also possible, it all depends on the distance between the frame stays.

Choice of components

Electro. bicycle ?

A special type of frame has been created for the most powerful motors and batteries. spatial. It has all the comfort benefits of double suspension thanks to its long travel shocks. The batteries in this frame are located in special cavities, which significantly increases the battery capacity and power reserve.

In appearance and speed capabilities, such an electric bike is more like a motorcycle. Lack of frame. its corresponding weight. It will not be easy to roll such a unit to the fifth floor.


Mountain double suspension with an electric motor is already much more comfortable. The presence of a front, and most importantly a rear shock absorber will make the ride dynamic and enjoyable. Two-suspension systems in their original form are considered to be narrowly directed devices, moreover, heavy. But when driving on electric traction, weight does not really matter to the bike. Shock absorbers with 50.200 mm travel will make the electric double suspension a real conqueror of the roads.

But often not everything is so good. The cons of a two-suspended frame can be written down to its specific structure. The rear shock absorber, taking up part of the inner space of the “triangle”, makes it difficult to install a standard battery. This is solved by individual assembly of batteries for a specific frame. The lack of rack mounts also raises the issue of battery placement.

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Frame and requirements for it

To begin with, you need to decide on the choice of frame. Often, existing bicycles are electrified. The most common. this is a mountain hardtail or full suspension. Consider the pros and cons of each type of possible “donor” and its frame.

Frame material selection

Bicycle frames are:

  • Steel. They slightly absorb shocks and vibrations when driving over bumps and facilitate handling when bending on bends. Their main drawback is their heavy weight. Modern steel frames are manufactured with the addition of chromium and molybdenum alloys. They provide products with high maintainability and extended service life. As the frame ages, cracks and rust appear on it. During the operation of the frame structure, it is necessary to update the outer enamel coating and treat the inner surfaces of the tubes with an anti-corrosion compound.
  • Aluminum. They are produced from different aluminum alloys with a 4-digit marking. For example, marking 7005 indicates the use of AlZn alloy, and 6061. AlSiCuMg. The service life of aluminum frame structures is up to 15 years. Their characteristic feature is the ability to accumulate fatigue and lose strength over time.

In terms of strength, modern aluminum frames are not inferior to steel counterparts, because manufactured using the latest technology. An important plus of aluminum frames is lightness and less susceptibility to corrosion. But in winter, when the roads are sprinkled with salt and reagents, you need to protect aluminum structures from their effects. monitor the paintwork and regularly wash the bike.

Aluminum frames are highly rigid. This property provides easier control of the bike, but also increases the rider’s feel on all road bumps. Therefore, to soften the stroke, you need to use shock absorbers. On the other hand, aluminum frames provide a better road feel, easy acceleration and access to slides.

  • From titanium alloys. Their advantages are light weight, shock-absorbing properties, high strength. On the other side of the scale. a high price.
  • From magnesium alloys. Such frame structures are durable, lightweight, and effectively dampen vibrations. But they are expensive and corrosive.
  • Carbon (carbon fiber). In addition to the price, they have some advantages: light weight, effective vibration damping, ride comfort, high durability. But under strong shock loads, carbon can crumble.

E-bike frame

In the design of an electric bike, all the components and elements are important: the motor-wheel, battery, controller, brake system, rims, forks, bicycle cameras and, of course, the frame. All major components are attached to it. The strength of the entire structure, the accuracy of the attachments, the service life of the bike, the safety and comfort of movement on it depend on which frame to choose for an e-bike.

E-bike frame dimensions

The size of a bicycle frame is usually determined by the length of the seat tube. For frames of classical design, it is measured from the axis of the carriage to the axis of the upper tube, in other cases. from the axis of the carriage to the upper border of the seat tube. The correct size depends on the height of the rider and is selected individually.