The fat bike is more problematic because one has to get a custom wheelset made with fat hubs to convert to 29r. No off the shelf sets available.

There is a guy in Colorado who does it a lot, and my plan was to order a set and pick up when I go to Moab next. Was set for this Nov just past until covid struck.

They make sus forks for fat bikes (bluto, mastedon) but I may explore a 29r fork that suits the geometry if possible. This would allow me to then use a stock 29r rim instead of a custom one. 29x3 = 26x4.6 for BB height.

Mostly this would be for mtbing so some geometry change might be acceptable. Even though the fat tires absorb some shock I cring a bit when hammering the rigid front end because I don't want to bend a rim.

Looking back, if I could do it all over again I would probably bought a 29x3" bike for this purpose, like the Surly ECR. The spacing of fat bikes is problematic, especially when considering repairs somewhere off the grid. I think, if I were to do an extended trip, I might have a second wheelset or at least hubs ready to go for shipping.

Then again, I bought the fat bike specifically because I want to explore places like the Great Sand Hills in Saskatchewan where my 26" bike could not make any headway.