I recently got a 27.5+ Fox fork only to discover that the distance between the legs of the fork is 4.3". This made me think that one could fit a 4" tire (obviously, using a 110 mm front hub instead of 150 mm) in there, and sure enough, after googling I found people doing exactly that.
So my question: can we consider 27.5+ forks a good alternative to 26 fat-specific forks such as Bluto/Mastodon?
Update: I did it, installed a 110mm Boost hub into an 80mm rim. It's not ideal because spokes are almost vertical. To make it work, you need:
- Either a 65mm or 52mm rim; or
- A 203mm brake rotor
Either of these two things fixes the problem. Apart from that, the experience is amazing. A 26/3.8 Hodag fits into a Fox Factory 34 27.5+ (plus!) wheel perfectly, affording about 4mm clearance each side (lots of space on top, maybe 2cm or so). Cornering, grip, much softer suspension — this is all vastly superior to what you get from RS Bluto or Mastodon Pro.
So if you're OK with a 3.8" front wheel, you can totally do Fox. For example, many electric fatbikes (e.g., Haibike FullFatSix) are limited to 4" on the rear, so having 3.8" on the front is not such a big deal. Here, I made a video about this.