You're welcome.  That bearing might not be quite the perfect specs for this application.  It seems like I've had to replace them more frequently that the originals.  We usually get a couple seasons out of them before the dreaded scratching of the fan impeller on the housing, although that tattle-tale sound lets you know when you need to replace one and you can usually sneak in 5-10 more acres.  For how cheap the bearings and seals are a guy could just replace them as preventative maintenance every year or two.  Buy extras and you can fix them quick in season.