Motor Strength for Friction drive E-Bikes

[serniko97]

Hello community, I'm new here and probably won't stay very long.
I'm sorry if this question has already been answered but I couldn't find it anywhere else.

I'm doing some research about friction drive ebikes to build one for myself and I saw quite a few cool projects from this forum with very detailed descriptions. Very nice!

I see that many use the outer case of the motor to make contact with the wheel and I'm concerned about it.
I never hold a brushless in my hand but I can see that the rotor is attached only on one side to the shaft. And the shaft is attached on both sides to the stator through bearings.

This doesn't seem very robust to me and since the rotor is being pushed to the wheel I'm concerned it might touch the stator on the inside.

What are you thoughts on this? Am I completely wrong? Are this brushless motor so rigid that are extremely difficult to flex?

Thank you very much

 

[Tommm]

Hello community, I'm new here and probably won't stay very long.
I'm sorry if this question has already been answered but I couldn't find it anywhere else.

I'm doing some research about friction drive ebikes to build one for myself and I saw quite a few cool projects from this forum with very detailed descriptions. Very nice!

I see that many use the outer case of the motor to make contact with the wheel and I'm concerned about it.
I never hold a brushless in my hand but I can see that the rotor is attached only on one side to the shaft. And the shaft is attached on both sides to the stator through bearings.

This doesn't seem very robust to me and since the rotor is being pushed to the wheel I'm concerned it might touch the stator on the inside.

What are you thoughts on this? Am I completely wrong? Are this brushless motor so rigid that are extremely difficult to flex?

Thank you very much

Not sure what you mean, if you want a friction drive, just clone the add-e drive. You need a motor and some cnc bits to bolt it up.
Their design only contacts the wheel when on the throttle, allowing freewheeling.

 

[serniko97]

Thank you for the reply!

Yes, I was looking for something like an add-e electric bike.
What I mean is the possibility of the external rotor to touch the internal stator on the side where it's not attached.

Because this brushless motors are not designed to handle a sideway force like in the case of a friction drive e-bike.
By the way since everybody apparently had no problems like this I'm probably wrong.

Do you think this motor and controller are okay for something cheap to get started and a peak power of 1000W?
https://www.aliexpress.com/item/4000416034651.html
https://www.ebay.it/itm/274468058715

 

[Tommm]

Thank you for the reply!

Yes, I was looking for something like an add-e electric bike.
What I mean is the possibility of the external rotor to touch the internal stator on the side where it's not attached.

Because this brushless motors are not designed to handle a sideway force like in the case of a friction drive e-bike.
By the way since everybody apparently had no problems like this I'm probably wrong.

Do you think this motor and controller are okay for something cheap to get started and a peak power of 1000W?
https://www.aliexpress.com/item/4000416034651.html
https://www.ebay.it/itm/274468058715

You need motors where part of the shell spins like they have. So non axle motors. For example these model airplane motors.

https://www.amazon.de/-/en/Reely-Brushless-Motor-R60-5050-510KV/dp/B076BVV175

This specific motor has bad reviews but you get the idea, I have seen plenty of them.

 

[Solcar]

Thank you for the reply!

Yes, I was looking for something like an add-e electric bike.
What I mean is the possibility of the external rotor to touch the internal stator on the side where it's not attached.

Because this brushless motors are not designed to handle a sideway force like in the case of a friction drive e-bike.
By the way since everybody apparently had no problems like this I'm probably wrong.

Do you think this motor and controller are okay for something cheap to get started and a peak power of 1000W?
https://www.aliexpress.com/item/4000416034651.html
https://www.ebay.it/itm/274468058715

I think you're onto something. I recall reading of friction drive builds with outrunner motors having extra supporting bearings added to the project because the standard skirt bearings in the motors aren't up to the task.