Hour-wheel is the last wheel that is placed on the dial side before the dial is put on.

It meshes with the minute wheel. It rotates in twelve hours and the hour hand is fixed on it.

In most cases it is the barrel, attached to the hour hand, which is fixed on this wheel, which is why it is also called a barrel wheel.

On more common quality watches, a foil is slipped between the hour-wheel and the dial to make the height clearance. However, these foils are not allowed by some certifications and are not very well seen because they add friction to the movement.