howdy y'all! so i'm completely new to 'bikepacking' and fat bikes / mountain bikes, but have done a fair amount of touring on a 29er road touring bike but i'm looking at getting into more off road bikepacking as opposed to road touring.

currently in Nicaragua and the riding has been a blast but for places where the road turns to a rocky pot hole filled mess it has been miserable on my road touring bike and has got me yearning for a 29+ (or 27.5+) touring set up. every 'plus bike' i look at it way out of my price range though, i don't know if it's just because it's a relatively new thing but they all seem to be super expensive. fat bikes however seem to be a bit more affordable and i'm sure they would kick ass on trails, but not so sure about putting in big distances on road with a fat bike.

so my question is this; without changing the rims on a fat bike would it be possible to just swap the tyres out on a fat bike to something slightly narrower to kind of change a fat bike to plus sized bike? like instead of a 3-4" tyre putting something like 2.5-2.8 tyre on a fat bike?

if this makes no sense it's probably because i'm dehydrated and bought a bottle of friggin fantastic nicaraguan rum.

any advice or if anyone has done something similar i'd really appreciate any input.

thank you!

-michael