I will take a closer look tonight at spray trajectory, I drove today. But I do not think that my BB gets to gritty from fender spray. I know my feet do get a little wet after an hour commute; but it is primarily water coming up through my cleats. But some water is expected.

When I got a full strip down service a few months ago the guy said my BB was as good as new and it has almost 10,000 km on it. They are hard gritty commuting pacific NW km also. The bike has always been fendered, so that must mean something.