Shimano tiagra 4600 rear road bike huba reliable rear hub for road cyclists like those at the top of the range tiagra road hubs feature labyrinth and contact seals to prevent the ingress of corrosion causing dirt and water this along with the internal grease sleeve both increase durability and reduce service intervals the hub uses angular contact bearings designed to cradle the balls giving both radial and lateral support for superior strength and durability in real world riding conditions