On 11/14/2018 11:02 AM, Joerg wrote:

I can't because my MTB doesn't even have the space for a single water
bottle of decent size. Even the bike dealer where I bought is said
"WHAT?? How could they now have that?". So I mounted one holder on the
handlebar (I have a bike with a cup holder now!) plus modded the rear
section for some heavy duty longhaul schlepping.

http://www.analogconsultants.com/ng/bike/Muddy4.JPG

I've seen several ingenious ways of carrying water bottles, even on
frames like yours. But I'm pretty sure they wouldn't work for you.

--
- Frank Krygowski