Fat bikes are great for loose and soft terrain. Sand, SNOW, mud, that sort of thing. But they are far less efficient than normal MTBs on harder packed surfaces.
They "say" they are good in snow. Realistically it has to be groomed snow.
- If there is any accumulation of fresh snow, I'm on a mountain bike or tire that can slice through the snow
- If there is ice or any freeze/thaw cycle, I'm on studded tires (Try pricing those out for a fat bike, lol).
- They are fun on groomed MTB trails, or simply following a snowmobile track.
- I can't ride in deep snow with them, but can on 2" or skinnier tires that cut through the snow.
- Some snow can't be ridden on much anything other than a fat bike - like old snow that has been walked on or driven on. I tend to avoid that stuff.
I agree, with good tires I can easily do 15mph on a fatbike. I love the way fat knobbies tend to part the seas when riding in an area with pedestrians. They tend to have super long wheelbases, which makes MTB trail riding a little different if its at all tight.