Abstract: A tensioner to provide resistance to rotation of a shaft relative to a surface from which the shaft originates. The tensioner comprise a shaft collar split into at least two pieces; at least one connector for fastening the split pieces of the shaft collar together about the shaft; and a bushing split into at least two pieces. The bushing is adapted to contact an interface between the shaft and the surface from which the shaft originates. At least one axially adjustable member corresponding to each bushing piece and having a corresponding axial guide within the shaft collar is insertable in the corresponding axial guide and adjustable to exert pressure upon the bushing to push the bushing into or against the interface. The tensioner may be adapted specifically for use with a side-view mirror shaft, such as is commonly found on pick-up trucks and the like, and may be adaptable for use in configurations with or without grommets as the interface between the shaft and a mounting bracket for the shaft.