St4 and M1000 uses 6005 2RSH on front. SKF Single row deep groove ball bearing with two rubber seals 25mm inside x 47mm outside x 12mm width
https://www.bearing-king.co.uk/beari...5x47x12mm/4244
M900 used 20mm inside x 47mm outside x 14mm width, so you may need to find some 14mm wide alternatives to the 6005?