Quote Originally Posted by spfautsch View Post
BTW vilefly the metal shielded bearing type you posted a pic of would be a problem for vented optis because they need to hold vacuum. The vent system might suck the grease out of that one not to mention letting unmetered air into the intake.
Are the stock ones sealed at the back then ? Otherwise they’d suffer the same. I’ll open mine up when I get back, it’s been a few years now since I was inside.
Mitch