[PoorInRichfield]

Even the inner tube solution isn't an ideal solution. Looking at pictures of other people's bikes with an inner tube hack in-place, the indentation on the back of the seat post makes a nice channel for water and dirt to run down into the frame and right past the inner tube. Hence, a good solution needs 2 parts:

1. Seal around top of seat tube that has a "fat section" that will fill the gap caused by the channel in the seat mast.
2. Cover for adjustment slot.

This person's bike actually has fenders on it as well, but the owner mentioned that water (and hence dirt) still gets in the frame when washing the bike.

 

[norcallincoln]

While I love my 2020 Domane SL7 Disc, I can't help but think that the seat post design is just begging for water and dirt to get into the frame. The binder bolt to tighten the seat post mast is a giant slot in the back of the seat tube which is a primo-place for overspray from the rear tire to go:

I think it would be nice if Trek devised a rubber "plug" for this hole to help keep water out, similar to the plug on the chain stay for the DuoTrap sensor:

Can you think of a way to seal that hole, but still allow access to it in the event that I need to remove or adjust my seat post?

I considered just putting some kind of tape over the whole, but obviously that would mean a new piece of tape each time I adjusted or removed the seat post, not to mention the build-up of tape residue.

I just bought a brand new domaine 6 etap. Today was my3rd ride and I noticed for the first time this uncovered slot for adjustment. After reading the thread here I will be going out and getting white electric tape to cover it. A design flaw indeed. Does trek expect people to ride in dust free, rain free conditions at all times?