On Mon, 31 Mar 2014 08:08:20 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

thunk fired this volley in
:

What happens if you put a bearing within a bearing - the outer race of
the inside one being the inner race of the outside one? Is friction
reduced? Is the maxiumum speed changed? Temp rise?

You increase any inherent 'play' in the system. Also since the 'middle
race' is no longer heat-sunk to a shaft or housing, risk the possibility
of heating it without any way to remove the heat.

OTOH, you've distributed the wear over at least twice as many rolling
elements, and if everything were perfect the balls and races would turn
more slowly than a conventional bearing. IF everything were perfect.

Lloyd

Early Royal Enfield motorcycles had a connecting rod bearing that was
free to move both in the rod big end and on the crankshaft.
--
Cheers,

John B.