Electric "tough bike"

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Some porn.
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There was quite a hassle with frame welding. At first try the rear arm ends bent inwards, so we made vertical cuts to already welded arms, bent them straight, welded support plates to keep them parallel and then at last welded the cuts together. And the whole frame spent some hours at oven @ 220C for stress relief. Today I cut support plates away and it stayed parallel.
Ther's rear suspension missing entirely yet, this, and rear dropouts are next big jobs.
 
vax said:
Some porn.
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There was quite a hassle with frame welding. At first try the rear arm ends bent inwards, so we made vertical cuts to already welded arms, bent them straight, welded support plates to keep them parallel and then at last welded the cuts together. And the whole frame spent some hours at oven @ 220C for stress relief. Today I cut support plates away and it stayed parallel.
Ther's rear suspension missing entirely yet, this, and rear dropouts are next big jobs.
Awesome.
What do you think of geometry?
Small 20" wheels? Hard to tell what it would be like to ride, I suspect nimble and plush.
Btw awesome 3d triangulation of the swing arm. Very cool
 
All I can say right now, that seating position will be more mtb than mx.
The saddle will also be mtb one, the saddle post attachment point will be at the top of "pylon".
Right where are two bolt holes, seatpost bracket will be between them.
 
That's an awesome frame. Amazing work. Sure beats the price of those expensive ebikes. Reallly Really Great bike. I've been lurking the E scooter/ebike posts and man the E Bikes are ridiculous.

Sweet build. Wonder how a 72v would be.
 
Just came across this - I've been working on a similar design, I look forward to seeing where you take this!

-JD
 
Nice looking, has lots of potential. But that 250W hub seems little underpowered for ebike with looks like this.
First thing is to get it running, can upgrade later if you need more power :)
I want to see it when it is running, I am from Tallinn :)

Meelis
 
About 250W hub:
It's all about being street legal. In real life I'm sure it can handle much more power. Also, I'm using 48V instead of 36V marked on the hub.
There's some issues, however. For example, I have to upgrade wires, current ones are really thin and will cause problems.
If I blow the motor, I can rewind it with thicker wire and less turns.
 
Rolling chassis.
Faults:
1. Rear spring too soft
Where to obtain? I reckon pitbike spring will be ok
2. Both tires flat, forgot to use spoke rubber ring...
3. Rear swingarm needs new bearings and proper assembly.

Next, I guess, will be electrical assembly.
There also will be small 40cc range extender.

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Bookmarked!.
My DM50 is fun as a conversion but it is truly awesome to see a PURPOSE built EV, Awesome job so far :), Looking forward to see it go when you get it finished.
 
Did first ride today.
I manged to fry one of the BMS boards, I'll get a new one tomorrow, costs 14EUR...
So, today, I hooked up temporary wiring and headed to street. It was wet and cold, so I only did couple of Kilometers.
As I suspected 20A @ 48V is not very thrilling ride. So, 50A controller with better motor will be next goal.
Said that, I must admit, that the chassis is success. It handles very nimble, suspension stiffness just the way I like it.
It's quite long frame and seating position is pretty foward leaning. Add very hard saddle, meaning it's not very comfy ride.
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jansevr, the battery is 20Ah.
Yes the motor is not very powerful, and it is slow too - must be low RPM motor. It doesn't go faster without load...
However, 1kw Kelly and motor doesn't get warm at all. Motor has 250W printed on side cover :) Maybe 50A kelly next?
I'll have a look on Cromotor.
 
That is a beautiful work you did. Subscribed.
 
ricklearned said:
Looks like those BMS boards could short on opposite battery terminal. Have you considered a centralized BMS?
Yes, I thought that could happen, and put extra insulation under bms boards.
Updates,
I'm currently building proper electric systems - solid state relays for switchoff, Dc-Dc for 12V systems.
The bms main board uses 12v since it' designed for cars.It has two 2A relays, that switch over, when one of the slave boards breaks loop circuit. I'm gonna use one of relays to feed the bms itsself (with parallel ignition switch) and other to drive main solid state relay. This way, when bms disengages relays, it's gonna auto-shutdown.
 
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