The frame design




The final design of the 35 M. high unicycle frame is the result of the determination of C.S. Abrahams (Apo) to reclaim the controversial world record and his accidental meeting with Jan Smit in 1995 when Mr. Smit was looking for juggling equipment for his son.


Besides his activities for large engineers firms (presently Grontmij Water & Waste Management), Jan Smit, BS. has his own company, 4XJS, for special projects.



Jan Smit is a specialist in devising extreme constructions.

He is practically friends with Newton, Hooke and Euler and has specialized in static and dynamic strength/rigidity questions as well as failure analysis. Constructions with minimum weight, minimum inertia, maximum strength and rigidity for complex load situations are ultimate challenges, especially when fatigue is also involved.


Jan translated the ideas of Apo in an extremely light and rigid construction combining aluminium and stainless steel.

The construction has been devised on the basis of mast constructions for sea-going sailing ships. After the design and static calculation the construction has been optimised using EEM-software.

The construction is lighter, more rigid and has a much lower inertia moment than the unicycle of 72 ft from 1980 so the only new challenge for Sem should be the height.