Selecting a suitable dc motor for Electrical Bike project

[ronaldcwh]

Hi all,
I am currently doing an electrical bicycle project. I am wondering how large a dc motor power rating that I needed for my project. According to this online calculator, ( http://www.kreuzotter.de/english/espeed.htm ), I have found out that approximate 110W motor power rating is needed to have speed of 20km/h.

So, I wondering what model of dc motor that available to purchase for me to do this project. In the Cytron website ( http://www.cytron.com.my/viewProduct.ph ... er%20Motor ) , I found this motor that is power rating of 350W. It seems to be too large for my project. Is there any lower rating, about 100W DC motor that is about similar to this (electric scooter motor) that I found?

Thanks, I appreciate your helps.

[yonghui]

i think you should take this motor:
http://www.cytron.com.my/viewProduct.ph ... ith%20Gear

the sprocket match the bicycle chain. moreover, the motor has the gearhead to increase the torque and reduce the rpm to a more suitable speed.

we dont worry the power is too large since motor driver can control the output power with PWM.
we will worry if the power of the motor is not enough to support the project.

u can refer this, people use the similar motor to driver the bicycle:

http://endless-sphere.com/forums/viewto ... &start=100