Japanese bearings are most popular because they are long haul bearings that stand up much to heat than their Chinese counterparts. Chinese bearings are for short haul and are a lower quality bearing than Japanese bearings.
Poor bearings or bearings in need of replacement cause heat. If you see black colour in your grease then repack your bearings immediately. The black colour is carbon caused by metal on metal wear.
If you see carbon black or mud coloured grease your bearings should be replaced.
When stopping after driving your trailer, place your hand on your wheel hub. If it is hot then you need to adjust and/or replace those bearings. Beware if your grease cap has fallen off. This is usually a sign of an over heated bearing.
Always check your bearings after a repack or bearing change. Good idea to drive 20 kilometres and check your hubs for heat. If you get 20 kilometres down the track then you are in good shape.
If you are replacing bearings then replace them with Japanese Bearings. Chinese bearings are mostly used by most Manufacturers and most Retail Stores. Some manufactures use Japanese bearings however not many retail stores are stocking them at this stage. Your bearing must say JAPAN on the actual bearing otherwise it is Chinese or Indian.
