Thank you so much Cinellipro for bumping this thread. I have a RM5.1 SE with a Sumiko Blackbird cartridge, and the rumble has irritated me since the day I got it. It seems to disappear once the music starts, but I knew it was lurking in the background, mucking things up. I saw Applechap's blog a long time ago and contacted Sumiko about a USA version of the fix, but could not get a response. I gave up and decided to live with it until I could afford a table upgrade. Anyway, after seeing this thread I ordered the grommets from Grainger, installed them with no problem, and the difference was like night and day! Amazing improvement. The new belt arrived today and after a quick listen, I think it helps too, although the fit seems looser than the old one.
I have 96 extra grommets if anybody needs any!
I have 96 extra grommets if anybody needs any!