Hub bearing grade?

"Pete Biggs" <[email hidden]> wrote in message
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Quoted message said:

What grade of bearing balls does Shimano use in XTR and DA hubs?

Use *grade 25* ball bearings....

"Pete Biggs" <[email hidden]> wrote in message
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Quoted message said:

What grade of bearing balls does Shimano use in XTR and DA hubs?

TIA ~PB

That's a good question. I've been wondering that for years, also what grade are XT/Ultriga & LX/105.
I wonder what it would cost to have a few tested? How the hell does one test a 1/4" ball to that
precision? Who has a device that precise. Also how does one know what he is getting when he buys Gr
25 bearings? Does Shimano & Campy? I usually use Gr 25 because they're not that much more expensive,
but I could be putting in gr 200. It's probably one of those deals where the grade is the least
important part. Probably the cleaning of the hubs, careful application & quality of the grease,
seating of the seals, straightness of the axle & threads, & adjustment of the cones are of far
greater importance. But I'll keep using Gr 25, it makes me feel better. John

PS I just remembered something. During WWII my aunt worked as a inspector @ a Timken bearing plant.
I remember her saying that she could spot bad roller bearings w/o holding any gage in her hand as
they rolled down a channel. And how fast & accurate she had to be to keep her job as an
inspector. I doubt that a large roller bearing back then was anywhere near as precise as a 1/4"
gr 25 ball bearing is, but still it must have been within +/- 0.0001". I suspect she used
indirect means, such as the sound a bad one makes, or it would roll down differently. Perhaps she
was just deluding her self. Or maybe in WWII no one really gave a [censored], & the inspection was just
a sham to satisfy the DOD. If you have ever seen the quality of the welding of a liberty ship,
you'll know what I mean. Come to think of it that's what most QA/QC is today. I guess what I'm
saying is that maybe it's not as hard to measure (what is gr 25, 0.000025"?)as it first sounds.
One things for sure, you ain't gona mike it that accurate.

Quoted message said:

PS I just remembered something.

What are you babbling about?

--
Phil, Squid-in-Training

Squid-in-Training said:

What are you babbling about?

? I understood it.

Guy
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