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<DIV><SPAN class=820554416-19062003><FONT face=Arial color=#0000ff size=2>Hi
Earl, Hi All,</FONT></SPAN></DIV>
<DIV><SPAN class=820554416-19062003><FONT face=Arial color=#0000ff size=2>Ball
bearings have "point" contacts, which is only true until pressure squashes the
metal into small patches.</FONT></SPAN></DIV>
<DIV><SPAN class=820554416-19062003><FONT face=Arial color=#0000ff size=2>More
balls are good, as long as they don't shrink. Bigger balls are good (you should
have seen this cat my buddy Steve owned!) and get better faster than
proportionally to diameter. Roller bearings have "line" contacts and are even
better.</FONT></SPAN></DIV>
<DIV><SPAN class=820554416-19062003><FONT face=Arial color=#0000ff
size=2>Generally, pinging is the culprit with contact stress fatigue. How about
bushings?</FONT></SPAN></DIV>
<DIV><SPAN class=820554416-19062003><FONT face=Arial color=#0000ff size=2>Dean
P.</FONT></SPAN></DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> EHaury@aol.com
[mailto:EHaury@aol.com]<BR><B>Sent:</B> Thursday, June 19, 2003 11:19
AM<BR><B>To:</B> discussion@nsrca.org<BR><B>Subject:</B> Re: OS After Run
Rituals<BR><BR></FONT></DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial
size=2 FAMILY="SANSSERIF">This is an excellent observation. While rust can
certainly do in a ball bearing, by far most of the bearing failures we see are
load failures. The larger the prop and higher the nitro the tougher it is on
the rear bearing. As 2-strokers have mostly downward loading on the bearing,
they seem most critical. Interesting that the 3M Mintor folks have chosen a
double row bearing for the 170. <BR><BR>Does anyone have comparative load
ratings for single and double row ball bearings of the same external
dimensions? How about larger / smaller / more / fewer bearing balls in the
same external dimension races? <BR><BR>Earl</FONT>
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