E-bike from scratch
 

Dear community,
I would like to build my own electric bike. I watched a lot of different videos on Youtube, but I could not really find what I searched for. As I mentioned in the title I want to build it from scratch. I don't want to use a kit.

So I thought about using a motor from Hobbyking like this one: Turnigy RotoMax 1.40 Brushless Outrunner Motor After a little bit of calculating I think I would need a gearbox with 1:30 to use such a motor on a bike.

At 35kmh the rpm of a 26inch wheel is 281rmp.
And the rpm of the motor at 37V is 8436rpm.
-> 1:30

I think with the appropriate ESC a controller and a battery this should work. But how can I convert the rmps?
What do you think? Am I right? Have you any suggestions how to use such a motor on a bicycle? Are there gearboxes I can use?

Thank you in advance!

If you want to get that technical, you want to be on endlesssphere.com

Are you thinking of a friction drive, or what?

I’m not sure why you want to re-invent the wheel. Is it for the technical challenge or to do something new? I doubt you’ll save any money over buying from a wholesaler like bmsbattery, elifebike greenbikekit or similar.

Look at the kits from BMSbattery, to give yourself a BOM (shopping list). 80-50% of the ebikes on the market use these basic parts as a building block em3ev.com has a lot of good technical data and some good kit ideas.. Go to ebike.ca calculator to design your components.