Figuring out how much torque dc motor will need to run at a certain speed. (E-skateboard project)
Get a friend to tow you behind a car while you ride a conventional skateboard. Use some type of spring scale to measure how hard the tow rope is pulling you. That force, multiplied by the radius of the skateboard wheel, is the required wheel torque. If your skateboard uses a drive-belt, then the motor torque will be different than the wheel torque. The rope should be long enough that you are not in the slipstream of the car. I suggest you take measurements at several speeds and also while going up and down a few hills. Make sure you record both speed and force. The speed component will allow you to calculate power as well as torque.