Koyo Bearings Koyo is the JTEKT Corporation brand for Bearings. JTEKT engineering and manufacturing capabilities range from super large bearings with outer diameters of seven meters to miniature bearings with inner diameters as small as one millimeter. Utilizing new materials and the latest in manufacturing technology, JTEKT Corporation has developed hybrid ceramic bearings and a variety of extreme special environment bearings to meet the increasingly severe and demanding requirements of modern industries. JTEKT Corporation stands at the forefront, as a technological leader in the world bearing industry.