Posted: Sat Feb 28, 2009 12:52 pmI started looking into replacing the open roller bearings in the Roots blower I have. This is in the interest of looking at costs involved with the different air mover types I am considering. The original bearings on the opposite end from the timing gears, are NDH R-1305 roller bearings. They are a 25mm id. X 62mm od. X 17mm th. They are a cylindrical roller bearing and the flanged inner race slides out easily towards the rotor, so there may be a small degree of thrust control away from the rotor. I cannot find an equivalent roller bearing in either a shielded or sealed type, probably due to the lack of inner race retention? Ball bearings in this size and seal configuration are widely available. The sealed ball bearings are rated at over 7000 rpm, so that would not be a limiting factor, but would a ball bearing be appropriate for this application? I am guessing they would be satisfactory due to the intermittant use and relatively low load (boost).