Shimano rs21 clincher wheels pair front wheel this rs21 clincher wheel offers excellent quality and durability at a competitive price steel butted and bladed straight pull spokes elbow less spokes make for a strong yet compliant wheel high lateral rigidity is maintained by using a wide flange spacing smooth high polished finish hub shell the hub uses angular contact bearings designed to cradle the balls giving both radial and lateral support for superior strength and durability in real