Quietest motor for making a mid-drive

[ebikeman123]

I was very inspired by the Vector Vortex that uses a large direct drive hub motor as a mid-drive. It is virtually silent, doesn't overheat, reliable, little unsprung weight and can climb almost any mountain. The only downside is that it is quite large and takes up precious space.

I would like to make a more normal looking e-bike, but with the advantages of this kind of setup. I understand it is this quiet because it is running at a relatively low rpm. Most mid-drives have small motors running high rpm and therefore make more noise. Are there high-quality motors out there that are smaller, but make little noise even at high rpms? A 15cm diameter motor or less would be ideal!

Check out the video second from the bottom! He silently climbs a mountain at a high speed!
https://vectorebike.com/gallery/video/23-vortex

 

[Vbruun]

I guess your best bet would be some kind of inrunner rated for much more power than you want/need.

But I think you are asking for something that is virtually impossible. The ability to make power goes Up with RPM and stator diameter so if you you want to decrease one, you have to increase the other.

But maybe some kind of helical gear or jackshaft reduction with belts can help you get what you want.
The motors don't male much noise beside fan noise when run in FOC

 

[Overclocker]

the qs 120 70h is a low-kv motor (38). not as "slow" as a hub but you probably won't find a lower kv that's readily available at a reasonable price. the BHT is 36kv but out of production

to keep noise low don't use anything smaller than 13t. and use a large spring-loaded rubber wheel to keep the chain tensioned

i don't care about noise so i'm using 10t :lol:

[youtube]9JjLhp5uX6w[/youtube]

 

[j bjork]

https://endless-sphere.com/forums/viewtopic.php?f=6&t=95745

Something like this?

 

[John in CR]

ebikeman,

What kind of power, all up load, and terrain do you plan to run. Most noise isn't from the motor itself, so you need a low Kv motor, which can make the drive train almost as quiet as a DD hubmotor unless you're going shaft drive with a very high quality gear reduction.