According to unicycle.com
The Nimbus Hatchet builds on the amazing platform that the Oregon created, and moves it onto the next level. The frame comes with the brake installed on a new precision IS mount. The hose is also clipped in place with special red aluminium clips. The main challenge with “Fat-Uni’s” is the requirement for a super wide frame. This can make it uncomfortable to ride as it catches the riders’ legs. To resolve this the Nimbus Hatchet moves the frame behind the riders legs giving maximum clearance. This also means you can run some of the largest tires on the market, which includes the Snowshoe 5.05" tire.
This frame will hold a tire up to 26" x 5.05", 27.5" x 4", 29" x 3.0" and a 32" x 2.125"
My observation is that real world tire diameter and fitment varies by manufacturer and setup. Ideally I’d love to run one of the new 27.5x4.5 barbagazi/gnarwall tires from bontrager but I fear that they exceed the suggested tire specs by to significant of a margin.
If you are running a hatchet with an aftermarket tire setup, please post your setup, and any comments about fitment and ride quality are greatly appreciated. Pics too.