The tiagra rs400 rear hub from shimano is a reliable rear hub for road cyclists like the top of the range front hubs rs400 tiagra level road hubs feature a 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 making sure you roll smother for longer the hub also uses angular contact bearings designed to cradle the balls giving both radial and lateral support for