# How can we calculate torque required to rotate the wheel (mass unknown)

Is it possible to calculate torque required to rotate wheel but weight of wheel is unknown?

• A wheel will rotate just as long as you can overcome the friction of the system. So even a very low torque motor can get a well balaced wheel system to rotate, its just going to take a long time to accelerate the system. So no with this info alone you can not answer anything. Not that knowing the wheel geometry helps – joojaa Aug 10 at 9:01
• Better yet, (since you didn't specify), what torque is required to rotate the wheel about a non-axle axis, when the wheel is spinning? (gyroscopic torque) – Carl Witthoft Aug 10 at 17:27

If and only if you know the power of the driving motor. The power-torque relation is: $$P = \omega T$$