re: 105: repacking wheel bearings

[James Montebello <jamesm@domain.elided>]

On Mon, 3 Feb 2003 TJCallahan@domain.elided wrote:
> Step 3. Pack the inside of the hub with grease. I always took the old stuff
> out (cleaned the hubs) and re-packed with new. I packed the hubs fairly solid
> (the spindle would push out a plug of grease as the spindle is mounted) but
> have been told I put too much in. I never experienced a wheel bearing
> failure, however.

I *have* experienced a wheel bearing failure, which appeared to be
caused by someone packing *way* too much grease into the bearing.
Can't speak directly for the 105, but the manual for the 116 states
that only 20 *grams* of grease should be used per bearing.  It doesn't
mention packing any grease into the hub itself, since only the bearings
are taking any load.  When I had a wheel bearing go, I found about 1
kg of grease in the bearings and hub, and the bearing had failed from
"skidding" rollers on the race.  Rolling element bearings don't need
much lubrication to do their job, and too much will damage them.

Having a lot of extra grease in the hub (as opposed to in the bearing
itself) probably won't cause any harm, but I don't see how it helps
anything, either.  20 grams is just enough to lightly coat the rollers
on a tapered roller bearing.  Seems like too little, but 5000 miles of
driving on this bearing suggests it isn't.

james montebello
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