Bearing "Selection

[dick kennedy]

All this talk of bearings reminds me of a conversation I had with an Opel
Engineer in R=FCsselsheim many years ago when we were first trying to sell
electronics in Europe. At dinner one evening the talk turned to engines
and he told us that American made bearings would not survive in their high
reving engines. The guy is now high up in the company and he was dead
serious about this.

I'm not a bearing expert but everything is sold to specification. A given
line could well be making parts for dozens of customers all with slightly
different specs. I would assume that's also standard practice in the
bearing world. The number of bearings used in all the GMC's ever made would
be completely insignificant to these people.

I don't understand why there is controversy here. Special tolerances are
just that and do not represent any kind of "Cream of the Crop" from the
view point of the manufacturer.=20

My 2 cents

Dick

 

[patrick flowers]

>
> I don't understand why there is controversy here. Special tolerances are
> just that and do not represent any kind of "Cream of the Crop" from the
> view point of the manufacturer.

Dick,

I don't disagree with anything you wrote. The only "controversy" is
whether there's anything truly different between the bearing set sold by
Cinnabar and a Timken Set 23 from any other source with .0095 axial
clearance.

Patrick
- --
Patrick Flowers
Mailtoatrick

The GMC Motorhome Page
http://www.gmcmotorhome.com

 

[patrick flowers]

>
> I'm not a bearing expert but everything is sold to specification. A given
> line could well be making parts for dozens of customers all with slightly
> different specs. I would assume that's also standard practice in the
> bearing world. The number of bearings used in all the GMC's ever made would
> be completely insignificant to these people.

I was a little too quick on the previous response. In order to
manufacture bearings at high volume and keep the price competitive, it
is critical for a bearing manufacturer to keep manufacturing tolerance
to a minimum. They expend tremendous amounts of effort to ensure the
uniformity of components coming into the assembly area. Therefore,
within one production lot, there will be no difference in
specification. For example, if you're looking into a bin containing
5,000,000 rollers 1mm x 15mm(been there, done that), there's no way to
distinguish one roller from another and any variation will be
microscopic. Once the bearings are assembled, then they can be sorted
by tolerance.

This is the crux of my assertion that the Timken Set 23 being sold by
Cinnabar as Part No. 12351677 differs only in axial clearance from those
available from other sources. The "20% additional load carrying
ability" must be due to the additional axial clearance. I can see no
other way to differentiate these bearing sets after manufacture and
would be eternally grateful to anyone who could enlighten me
otherwise.

Patrick
- --
Patrick Flowers
Mailtoatrick

The GMC Motorhome Page
http://www.gmcmotorhome.com