"That bike must be really heavy, does it have an engine ?"
As spoken to me by an elderly Italian guy this morning when I went to grab a coffee.
I think that what was once seen as a fad has now become mainstream... in 2006 Surly only made 600 Pugsley's as they did not know how well they would be recieved and now there is a broad range of models, the tyres have gotten even wider, and it is not quite as unusual to see a Fatbike.
Surly did not invent the Fatbike... but they seem to be most responsible for popularizing it and in doing so have expanded the market for parts.
Once considered a beast that was better suited to muskeg, trails, mud, sandy beaches, and snowy conditions there are a lot of people buying them for urban assaults because the big comfy tyres, comfortable riding position, and stability that makes you feel like a trials rider is something that balloon tyred cruisers offer but they don't have the same insane ability to go pretty much anywhere.
My back prefers to be stretched out and with the drop bars my position improves so much that I discovered how fast this bike can go on the street and with the tyres at 15 psi it rolls out really well.
In the winter it excels on snow... but without studs is about as scary as they come on ice as there is no contact pressure under those 4 inch tyres. I have a dedicated winter bike that rolls on studded tyres and it did not see as much use this past winter as the Pug handled things really well.
My favourite place to ride is down along the river and in the river where standard bikes just wallow... the Pug barely leaves a trace of it's passing so in that it is very trail friendly.
So... roll up your own big fattie.