The Oracle is the first of the Nimbus line up to use 6000 series aluminum for a frame. Nimbus chose the classic round crown design for better knee clearance and strength without adding weight.

The Nimbus Oracle frame now comes with the disc brake mounting tab welded to the frame. This design is aimed at the serious unicycle rider offering design advantages that add to the riders current performance.  On the rear of the frame there are hose clips for your brake cable keeping it out of the way. 

The biggest tire that will fit is a 29 x 3.0" tire without hitting.

Features: 

Size: 29" (27.5)
Length of seat tube: 140mm 
Material: 6000 series aluminum 
Inside diameter seat tube: 25.4mm (seat post diameter) 
Outside diameter seat tube: 31.8mm (clamp inside diameter) 
Diameter Bearing holder: 42mm (bearing outside diameter)
Bearing pitch: 100mm (center bearing to center bearing) 
Weight: 658g (incl. bearing holders and bolts) 
Comes with: Welded IS disc mount, bearing housing and bolts