10Kw street bike

k10e3r

1 mW
Joined
Jul 30, 2021
Messages
19
Hello every one.
I'm new here and posting to share and have advices.
So here is a 10Kw street bike project I'm working on.
The goal is to have a bike for daly use and about 2h run time for week ends.

26" wheels, 1200mm wheel base, Front 60mm wide, rear 80mm
MOTOR: 12090 Outrunner, 130KV, 18KW max, (watercooling later)
ESC: 3-22S 400 A Watecooled
Pack: 18650 Li-ion 14s x 28p ~50V 78Ah
BMS: Daly 14S 250A Li-Ion

I did some drawing, a mixture of a moto3 and e-bike
A lot of questions still open??? But will ask step by step
Frame should be aluminium or fibre...

Let me know if you have doutes on any point.
 

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I don't use rear break muck. Motor break could be enouth. I Only use the rear when the front is sketshy or to tighten turns.
The motor is small so it shoud fit there. I might use an old frame to start with. Motor might be lower, half way under the swingarm.
As long as the weigth is close to the rotation point it shouldn't affect rear suspention so much. Also easyer to swich to belt drive as the suspention doesn't affect chain length.
 
Well. Had to start some where :wink:
 

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Looks interesting, I guess you are going for very light weight? (with those wheels etc.)
Are you sure your motor is up for the task?
I dont know anything about it, but I guess it is something for an rc plane?
They seem to usually only be able to perform somewhere close to spec when cooled by the propeller.
130kv and single stage reduction?

I'm thinking the qs 138 70h with reduction built in would be something for a build like this, but maybe too heavy and big.
Why 14s?
Your swing arm looks heavy for a lightweight build?
 
Yes. It's a motor for rc planes. Rated 10Kw constant and 18Kw max.
I will make a water cooling for the stator to protect the magnets from overheating. The esc has already a cooling system.
From my experience it's better for the mosfets to push a small motor than to have high curent peaks with bigger motors.
If weight is low and earodynamic is not to bad 10Kw should be enouth for daly use.
The thing is I like speed so if I have power I will use it :twisted: Also riding on track with small bikes zxr400l, 750ss, CB350f.

Want to go lightweight. The swing arm is just for testing. I will do one in aluminium when I'll build the frame.
It's my first real electic bike so I'm mounting things first in a 125cc frame just to have some experiance before making my own frame.
Coundn't find any afordable moto3 frame. So I'm going cheap first and will upgrade it as I'm facing problems.
Making everything from scratsh is risky because I lack of experiance.

14S because under 50V you can't get electric shocks. But I bought an esc for 22S 400A So I can go 80V later and gear the motor. I have a CNC mill so that's ok. Idealy ( motor -> pignon/pignon -> belt-drive -> Wheel)
 

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k10e3r said:
... Rated 10Kw constant and 18Kw max...
But these planes fly only a few minutes, not half an hour. I would implement the water cooling from the beginning.
k10e3r said:
...14S because under 50V you can't get electric shocks...
There is no problem with 72-90V DC , you can feel it, but it doesn´t hurt.
 
I didn't aim more than 90km/h
But you are surely right bicicle tires whon't hold the speed.

If I beleave Ri and Io given here:
https://alienpowersystem.com/shop/brushless-motors/120mm/12090-outrunner-brushless-motor-130kv-15000w/

@ 50.52A : 50,37V 2 546W 6 548rpm 266,8Ncm 67,3%Efficiency
@ 101,55A : 50,34V 5 118W 6 544rpm 666,9Ncm 83,6%Efficiency
@ 152,58A : 50,30V 7 690W 6 539rpm 1 067,0Ncm 89,0%Efficiency
@ 250,64A : 50.24V 12 834W 6 531rpm 1 867,3Ncm 93,2%Efficiency

(Kv load= 80% Kv)
With gear 12/79 I get Vmax= 99km/h
 

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Nice build Overclocker
I like the tube in the swing arm where the suspention is pushing on.
My project should be heavyer, cells + fairing etc.

Ok you both convinced me about the limits of the tires I chose!
 
what’s the torque limit for regular 26” rims with 32 spokes? I see people opting for rims with directional spoke holes for mopeds or is that mainly a hub motor issue? If I know a rough limit I’d bother to do the math to see if what I’m making will rip itself apart and maybe set a current limit.
 
Hummina Shadeeba said:
what’s the torque limit for regular 26” rims with 32 spokes? I see people opting for rims with directional spoke holes for mopeds or is that mainly a hub motor issue? If I know a rough limit I’d bother to do the math to see if what I’m making will rip itself apart and maybe set a current limit.


surron rear hub.jpg

rear hub of the surron w/ 12g spokes and motorcycle rim

bicycle hubs spokes rims tires aren't designed for motorcycle loads
 
The project is rather a moped than a motorbike.

For the sprokes I thought of 2.5mm The hubs are rather thick so looks coherent to me.
I found this fairing. Wanted it to be thin so I can put my knees close together.
 

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Direction it's taking...
 

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Nice project.
I agree on the moped/motorcycle tires instead of bicycle tires if you are going to race (high load and temperature) with the bike.
 
I looked for tronger 17" wheels. Difficult to find any thing under 20kg.
But I'ts not a race bike at all.
The goal is lightweight and aerodynamic to reduce consumption.

Here is a project that inspired me.
 

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With what looks to be not much gearing and a high voltage won’t you need a much lower kv motor?
I’m also doing a 26” wheel and 130kv motor and need to gear it down 12:1 with only 60 volts and will still be too fast at 40+mph
 
k10e3r said:
Here is a project that inspired me.

Yup. That is Safe's old bike. It was the first thing I thought of when I saw your drawings. There was an e-bike maker, years ago, on the west coast, who did a hubbie-to-mid-drive cafe racer he was selling. Old age has stolen his name from me now.
 
I guess I chose the wrong winding for one reduction 12->80 1/6,6
I made a xls to compare:
 

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k10e3r said:
I looked for tronger 17" wheels. Difficult to find any thing under 20kg.
But I'ts not a race bike at all.
The goal is lightweight and aerodynamic to reduce consumption.

Here is a project that inspired me.

how much current and what top speed do you plan to do?



maybe if trying to reduce consumption you could add more gearing with a freewheeling crankset as jackshaft. what i found recently and using to get 12.1:1.

ive been thinking about going for a more aero position on a typical mountain bike frame and other than dropping the saddle and bars way down and using really narrow bars I'm out of ideas. the electric bike above that's your inspiration with the long down/top tube it seems very laid out with head forward, i think id want the pedals under me more for comfort and control.

its like this position.
https://www.youtube.com/watch?v=Ore4K-eVC0E&t=68s aero but nothing extra. maybe could even be comfortable and can imagine a fiberglass version where youre sitting on shins and forearms. but how much do the fairings help vs a low position like this?


this rocket bike has pedals and does 333km/h. https://www.youtube.com/watch?v=WREyAicJXkM

wonder how aero this is?
https://i.pinimg.com/originals/da/cc/12/dacc12bc3ceff17e4ed18a648b0450d5.jpg

a fairing over the front wheel alone sounds unobstructive


your profile pic looks pretty comfy and aero but looks like you have no feet. i keep wanting to push you lower down and between the wheels instead of perched on top so much like a normal bike. so much room down below could go if not using a crankset and just staying away from off-road. long wheelbase for rocket starts.
 

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I want to make a "reasonable" bike, so 40mph in about 5 seconds and go to a top speed of 60mph is enouth for me.

Weight is importent because it increases the time you have high curent for acceleration.
Regarding aerodynamic It's compromices betwean confort, control and performances.
I'm used to this position from my track bikes but if you ride for houres like this it's difficult for your arms.

The problem of going low is the suspention. It is possible if you make a longer bike but this means more weight and affects handling.
Being high is to my opinion not so problematic if you don't aim pure performance. Wheels are not verry thick and the fairing on the upper part of the wheel reduces drag of the sprooks.

The problem is the large front surface of the driver. That's where the fairing becomes interesting to get "claean" airflow betwean the fairing and the driver.

https://bikeadvice.in/aerodynamics-speed-explained-in-simple-terms/
https://aip.scitation.org/doi/pdf/10.1063/5.0025199

On the track at the end of the streight when you put your boeady up for breaking you realy feal the drag on your boady. Verry effective to slow the bike down. It eaven makes it turn when you lean to the side.
 

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Partially playing devil’s advocate. I like that latest design. How will u make and mount the fairings
What esc and how many amps you using?
 
Maybe my physics lessons are too long ago, but in my mind, aerodynamics do not play a big role at low speeds.
Speed enters the aerodynamic resistance formula in square, e.g. double speed = 4 times the resistance, triple speed=9 times.
It doesnt make sense to compare a racing motorbike (with far more than 200km/h topspeed)
with a commuting vehicle for usage in public streets where you usually have (low) speed limits.
 
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