Well-base rim

A wheel rim with a central channel or recess into which one side of the tire bead can drop; the other side can then be forced over the rim for fitting or removal. Wheels with well-base rims are commonly used on passenger cars because they enable easy installation and removal of the tire; the seats of the rim on which the tire sits (rim flanges) have a 5° taper so that, as the tire is inflated, the beads are forced up the taper to give a wedge fit and a good seal for tubeless tires; safety bead seats must also be incorporated, however