If the wheel is rotated, does the bar experience a lateral force (perpendicular to the bar)? What if the rotation speeds up impulsively: will the bar experience a lateral force then?
In a vacuum acceleration is all towards the centre of rotation. Acceleration and force are vectors in the same direction, hence with no lateral acceleration there is no lateral force.
In the real world it's not in a vacuum and hence there is an additional force acting on the bar, caused by drag. This drag is lateral to the bar.
An increase/decrease in rotational speed (assuming the impulse for this change of speed comes from a torque at the centre of rotation) would cause an angular acceleration, i.e. the acceleration would not be towards the centre of rotation. As previously mentioned, acceleration and force are vectors in the same direction, hence the angular acceleration (which is lateral to the bar if taken over an infinitely small time period) would result in a lateral force on the bar.