Exciting news..!! Now, throughout the entire un-braked range, we will be using the AL-KO Optima Hub with waterproof, compact sealed bearings. Tried, Tested and Guaranteed Since the change of axle style to allow more adjustment throughout the EXT300 - EXT500 range, we have tried several different options available from AL-KO, the firm favourite being the AL-KO Optima Hub complete with the maintenance free waterproof compact sealed bearing. We have had great success with the Op