Sealed Bearings

"John B." wrote in message
...
On Tue, 31 May 2016 21:38:48 +0100, "Ian Field"
wrote:



wrote in message
...
With all the bikes I have I also have a bike for which I built the
wheels
on old Campy record hub on the back and DuraAce on the front.

After getting this bike back from a friend who was saving it for me
while
I was not in the best of health I rebuilt the wheels with new balls and
Campy grease.

I have mostly modern wheelsets from Campy or Fulcrum (the people who
make
the modern Campy hubs etc.) These wheels have sealed bearings. These
sort
of bothered me when I saw them because of the drag of the seals. You can
tell simply spinning the wheels in a stand. But I imagined that with the
weight of a person this would be insignificant.

For the last couple of days I have been riding the old Look and in fact
you CAN feel the difference between the open bearings and the sealed. It
does coast much further and with less noise.


If you mean regular bearings like the ones used for gear box shafts;
there's
a choice between shielded and oil seal bearings.

The oil seal type have noticeable friction, while AFAIK: the shielded type
just have a stainless steel shield that doesn't have any actual contact
with
the inner ring.

The oil seal type are only unavoidable if you need to contain oil.
The shielded type are OK with grease, but not 100% at keeping road grit
out.

You over simplify, There are basically three types of cartridge
bearing. Plain (open, no seals or shields), Shielded and Sealed.

Evidently not simple enough for you - the discussion was not about open
bearings.