A constant velocity ratio universal joint of the tripode type comprising an outer joint member (10) with tracks (12) and an inner joint member (15) having arms (17) carrying respective roller assemblies able to tilt relative to the arms and cooperating with guide surfaces (14) of the tracks (12) to maintain the roller assemblies in substantially constant orientation within the tracks, wherein each roller assembly has a retaining element (26) which has at least a surface of low-friction polymeric material engaging the guide surface of the track to maintain the orientation of the roller assembly.
