Bronze Age Clockpunk

This is a cool idea. A spell to create a perpetual wheel and then tie that to a bronze age setting.

Continual Wheel
Transmutation
Level: Clr 3, Sor/Wiz 2
Components: V, S, M
Casting Time: 1 standard action
Range: Touch
Target: Wheel touched
Effect: Magical Propulsive force
Duration: Permanent
Saving Throw: None
Spell Resistance: No

The affected wheel begins to rotate at a constant rate, adjusted by friction and other load. The force turning the wheel has an effective STR of 16, equal to a light warhorse, and the wheel can achieve a mximum rotational speed of 240 rpm. The wheel can be made of any material and in any shape, but it must be recognizably a wheel, can be no larger than 4 foot in diameter, no smaller than 6 inches in diameter and must be rimmed with some form of metal. It must also be joined or attached to an axle of some type, also with some type of metal. If the wheel is removed from the axle, the spell is broken.

Material Component
You sprinkle gold dust (worth 50 gp) on the wheel.

Lots of cool things you could do with that, both mechanically and socially. Endlessly spinning water wheels pumping water into tanks for plumbing, armored war chariots with arrow slits, ships that do not require rowers or sails, the ideas are endless.