Rims for pneumatic tires

A rim for a pneumatic tire and rim assembly which may be used when the tire is in a deflated state comprising an outboard rim part and an inboard rim part detachably secured together, the profile of the outboard rim part considered in a plane containing the axis of the rim comprising, in sequence, a radially extending bead retaining flange having a radially outer edge which is turned axially outwardly of the rim to provide a support surface of substantial axial width for the sidewall of a pneumatic tire, a curved seating region for the heel of a tire bead extending into a frusto-conical bead seating region tapering radially inwardly towards the axially inner region of the rim and extending axially inwardly to a radially inwardly curving bead toe seating region having a radius of curvature in the range 5 to 9 millimeters;

• the curved toe seating region terminating in a plane spaced axially at a distance in the range 18 to 20 millimeters from the plane of the inner surface of the bead retaining flange, the inboard rim part being joined to the outboard rim part in the plane of termination of the said curved toe seating region and when considered in a plane containing the axis of the rim having a profile adjacent said plane of termination which substantially mirrors that of said curved toe seating region and leads into an axially extending base portion having a diameter lying in the range 2 to 3 millimeters less than the nominal rim diameter as measured at the point where the plane of the inner surface of the bead retaining flange joins a line tangential to the inclined bead seating portion, the base portion terminating in a second frusto-conical bead seating region which increases in diameter towards the end remote from the outboard rim part, the second bead seating region terminating in a curved heel seating region and tire bead retaining flange the profiles of which considered in a plane containing the axis of the rim substantially mirror the corresponding profiles of the outboard rim part, the bead seating region of each rim part being inclined radially inwardly at an angle of 5.degree.to the axis of the rim.