VXB or FAG bearings?? recommendations?

[BruceM]

My Grainger NTN replacement ST-3 bearings are getting a little bit noisy at about 1000 hrs of generator run time.  I have to use quite a bit of belt tension on the serpentine belt to avoid belt chirp, so I guess this is the price I pay.

At Amazon, I find that VXB.com in California carries the 6307 and 6305 bearings I need in the RS (sealed) style. They are a pretty good price at $15 and $10. with free shipping on my Prime acct.  Are these crap?

I can also get FAG brand bearings, for $25 each.

Any thoughts on better bearing brands and/or sources???

[dieselgman]

FAG or Japanese NTN are good bearings and should run out at minimum 10,000 hours in typical generator service. A 1,000-hour life span is woefully inadequate in a generator head.

VXB carries all sorts of bearings, including SKF which are good if from original manufacturer, you get what you pay for! I would recommend the highest quality name brands and consider that cheap insurance against the potential for generator failure if a bearing completely failed in service.


dieselgman

[BruceM]

Thanks for the advice dieselgman.  VXB didn't have any name brand bearings in the sized needed so I ordered a FAG set.
1000 hrs on the NTN bearings is pretty disappointing, they were quite expensive via Grainger.

[mobile_bob]

its been a number of years, but from my experience
just because a brg has the right part number and is sealed well does not make
it a motor quality brg.

motors and generators run long hours it must be assumed by the manufactures, so they spec a higher set of standards for the brgs used in them, commonly referred to a "motor" grade.

presumably better grade materials, better seals and better steel, tighter tolerances, and probably equally important a higher temp grease.

i used to swap out a lot of brgs on 3 phase motors used to drive component saws in the truss plants i maintained.  simply taking a part number to a brg house pretty much assured me a job i would be revisiting within 6 months to a year, and i was asking for name brand stuff!

it wasn't until i presented the brg to the sales counter and asked for "motor" grade replacments did i finally get the problem solved.

i can only imagine that higher belt tensions and loads, result in more of the pounding being transmitted from our single cylinder engine's into the races and balls of these brgs.  when this is happening to a brg made to looser tolerances, the hammer gets a longer stroke so to speak.  a longer stroke of the hammer results in significantly shorter lifespan of the brgs.

fwiw

bob g