A band-type well obstructor for obstructing the well of the hub of a wheel rim, particularly for a pneumatic tire. The well obstructor has an inextensible band with integral circular protrustions mechanically extruded onto the band. The circular protrusions extend radially inwardly to abut against the base of the well to retain the band in position surrounding the well, and to resist crushing under the weight of the vehicle in the event of deflation of the tire. The well obstructor has a fastener assembly utilizing a screw with a groove adapted to receive a locking ring. The fastener assembly further has two transverse beams, one of which is adapted to fit over the end of the screw and abut against a locking washer placed between the transverse beam and the head of the screw. The locking ring is then snapped into place to hold this transverse beam in position. The second transverse beam is placed over the threaded end of the screw. This transverse beam has a countersunk notch on its lower portion which is adapted to receive a nut and to prevent relative rotation of the nut with respect to the second transverse beam.