Harry Travis wrote:

Have there been thin seals, rubber donuts, or gaskets that would
rest between the bearing cages and cups to reduce the amount of
water that can contaminate bottom bracket bearings?

yes, there are several pre-cartridge designs that have them.

I wondered whether in wet climates, say England, such existed,
before sealed bottom brackets appeared.

trouble is, for those kind of BB's, the moisture usually gets into
the bearing from within, not without. i.e. down the seat tube,
etc. the best solution is to drill the BB to allow water an exit
rather than keep it in where it causes harm. many higher quality
frames come with pre-drilled BB's for exactly this purpose.
particularly when used in conjunction with marine grease, such a
simple device is remarkably effective.

I think I've read the complete Jobst Brandt. Doesn't help me much
in this inquiry.

I don't recall writing about cartridge bearings but I mentioned what
occurs when water gets into ball bearings, especially in wheels. It
produces intermittent sharp cracking sound that don't sound like ball
bearings. That seems to be the fine oxide particles (rust) being
crushed. When this occurs, the bearing balls and cup and cone should
be wiped clean and lubricated. Bering balls will have a reddish gold
color but are not dimensionally damaged so they should be reused.

This is really simple. I look at the gap between a Campy cup and
the spindle, and say: I'd like to reduce by 95% the amount of water
that creeps in when riding in the rain, and I'm willing to put out
5-50 times the number watts I'd save from switching from metal to
ceramic balls to do it. smile Even 5 watts. I don't expect the
BB grease to NOT get contaminated and soapy from water. I'd just
like to extend the service interval from 1000 miles and 2 months to
5000 miles and 1 year. Is there a Teflon-coated neoprene-like
gasket that will do that?

It takes only a slight amount of water and that amount readily
emulsifies oil of the grease and causes water-in-bearing clicking
syndrome. No water should be getting into the lubricant at all and if
it is suspected to have gotten in there, the bearing should be cleaned
and re-lubricated.

Let me put it another way: Lizard Skins sells a big condom for your
headset bearings. Does it increase friction? No doubt. Leak-proof.
Probably not. Reduce headset maintenance? Likely.

Or, Andrew: If you put super-heavy grease between the ball bearing
carrier and the cup: Does/would that reduce water contamination?

That doesn't work. As far as a rubber boot goes, it must be a tight
fit on the upper half and have clearance like a skirt to not cause
drag, but even more important is that it not give a sliding capillary
path for water to climb up into the bearing.

Jobst Brandt