Action Constraint messing with scale?

I wanted to make the location of an object control the turning of a wheel by using an Action Constraint. (I know I could use a driver but just trying to test out my understanding of Action Editor and Action Constraints)

For some reason, when the control object moves, the wheel turns but also gets disproportionately scaled… anyone know why? Did I fail to Apply Scale before creating an action?

I’ve attached my blend file.

Thanks in advance!


action_wheel_start3.blend (469 KB)