Need some help building a friction drive

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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evbkezzz   1 mW

1 mW
Posts: 16
Joined: Jul 02 2019 11:30pm

Need some help building a friction drive

Post by evbkezzz » Jul 03 2019 3:05am

Hey all!
I am new to the forum and ebikes as well. I would like to build a ebike myself. I read posts from Kepler,adrian_sm and crossbreak! Great work and thanks for documenting it here.
This is going to be my first build and I have few questions ahead. Hope you guys help me with it.

Here is what I am trying to achieve:
1) control engagement and disengagement using the front derailleurs (I read about this from crossbreak's post here)
2) Keep the motor power at or below 250W still being able to achieve 25Km/hr without pedal assist.
3) Climbs hill with a incline of 15deg

What motors should I be using on my build? I researched some posts here on the forum and get the idea that 200kv is the right choice. But have no understanding why. Am I correct? Should I stick to a 200kv motor?
I also read that the speed depends on the diameter of the drive wheel and for a 2.5in drive wheel 2000rpm is required for speed of 25km/hr.
Should I drive the motor shell directly or should I use a coating of sandpaper or rubber? Sandpaper provides best cof but wears out the tires pretty soon... Couldn't get much info on rubber.... is there something that can hit a number between?
Coming to the tires, what kinda tires should I use? flat centre region?
If I want to be able to accelerate the cycle from rest, should I stick to using smaller rollers? I read large rollers have terrible low end power.. How does the diameter of the roller affect the power delivery? speed? torque?


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