Keith,
At high speed most of the heat comes from the pumping losses associated with
the churning of the oil in the bearing. Grease and oil baths work great at
low speeds, but higher speed bearings use jet lube, where the oil is sprayed
into the bearing and allowed to drain out. At higher speeds an air/oil mist
is used, and best of all is under race lube, where the oil is supplied
through a gun-drilled hole down the center of the shaft, then feed into the
bearing through tiny holes in the inner race of the bearing, the centrifugal
forces sling the oil from the inner race across the rolling elements and on
to the outer race, with a vacuum pump drawing the oil off and back to the
reservoir (sort of like a dry sump system). In industrial applications I
have seen big 4" bearings under 1000 lb. loads running around 20,000 rpm for
over 10,000 hours without service. Depending on tire size that is the
equivalent of running 1200 to 1400 mph for over a year !!!
On the other hand you probably did not want to spend $60,000 per wheel for
bearings.
The point is that the oil creates the heat at high speeds rather than
dissipating it, so use as little as possible of the thinnest oil possible.
Greg
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net]On Behalf Of Keith Turk
Sent: Thursday, May 24, 2001 12:09 PM
To: land-speed@autox.team.net
Subject: Axle Grease
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