Abstract: A releasable fifth wheel for use with a skateboard having an upwardly sloped tail portion cantilevered out beyond the rear race which includes a caster with swivel connected yoke and stem with the yoke supporting a plastic wheel. The stem includes a manually operable spring biased rod that has an indentation between its ends and co-acts with a ball detent. A pair of threadably engageable shells with flanges at their outer ends are adapted to be received in an opening in the skateboard tail. One of the shells has an internal groove which cooperatively locks the ball detent or releases the ball when the rod is moved longitudinally or rotationally.