Unicycle.com:

The worlds first unicycle frame built specifically for 29 inch wheels!

Unicycle.com has specially designed and developed this Nimbus unicrown frame to accept large 29″ tyres. The Nimbus 29″ frame will fit the biggest 29″ tyre there is - the Schwalbe Big Apple tyre (29×2.35″) - with room to spare. Tyre clearance is no longer an issue with a Nimbus 29″ frame!

Cromoly steel tubing is used throughout. The frameset is then finished with chrome plating for durability. Features split bearing housings and quality seat clamp and quick release. Comes complete with bearing cups and bolts. The inside diameter of the seat tube is 25.4mm, the new unicycle standard. You’ll need a 25.4mm seatpost to fit this frame, available in the Seat Posts section of our catalogue. The old 22.0mm diameter seatposts will NOT fit.