Before replacing bearings, confirm bearing size – the number for the bearing size is listed on the rubber seal of the bearing of your wheels. Currently, HED front disc brake hubs use 6902 bearings and HED front rim brake hubs (with radial lacing) use 6900 bearings. For wheels made prior to 2015, and any older front radial hubs, use 6901 bearings. For five pawl hubs and three pawl hubs dating back to 2013, use 6902 bearings. Three pawl hubs dating 2010-2012 use 1526 in the hub shell and 6902 in the cassette body. Numbers are on the rubber seal of the bearing, it is best to confirm size.