Should I seal the open spoke holes on my front rim? I have a 16 spoke front wheel on my road bike.  The hub is an oddball Shimano one with 16 big nipples at the hub end instead of the rim end.

This wheel also has a 32 hole aluminium/aluminum rim:



I washed the bike in the weekend and dried it in the sun, then hung it up.  On the first ride I pushed it for half-a-wheel revolution, and water came out of the rimholes that were at the bottom and are now at the top.  Total quantity was perhaps a couple of tablespoons worth?

Should I seal up the 16 open holes with something?  Theres no way they'll ever be used for spokes.

I don't know if this was the original rim or hub, given its a 1998 bike there's a good change its been replaced.



EDIT 2 years later I have retired this wheel.  It broke a single spoke on a downhill road at about 50 km/h (35 mph) and the sudden lack of true made it rub the brake/fork while shaking madly.

The spoke broke toward the hub end, so I still had the oversized nipple stuck in the hub and the rest of the spoke was hanging from the rim.  My suspicion is the spoke was weak from someone (maybe me) holding it badly while truing which weakened the metal with a score/scratch.

If one more spoke broke it could have locked up with a nasty full speed prang.  A normal 32 spoke wheel could survive the loss of multiple  spokes before becoming unrideable.

I did replace the dead spoke, but all of them have a phenomenal level of tension on them, which is also a concern.  For now, its hanging on a hook as a spare wheel.
It would be best if you could get 16 hole rim (yeah I know the may be hard to find). Holes on the rim go in the zig-zag pattern, and since you skip every second, all your spokes are on one (zig) side of the wheel. This is less than ideal, and in my humble opinion bigger concern than rain coming in empty holes.