A wheel assembly includes a first hub assembly sealingly engageable with a first axial opening in one side of a tire. A second hub assembly is sealingly engageable with a second axial opening on the other side of the tire. The hub assemblies define between them a fluid tight volume within the tire. The wheel further includes a valve having an inlet port in fluid communication with the tire, a valve seat, and at least one annular valve member resiliently biased into unidirectional sealing engagement with the seat. Application of external pressure through the inlet port causes at least a portion of the valve member to resiliently deflect away from the valve seat to thereby open the valve and permit fluid communication with the fluid tight volume.