Above is design, below is what remains of a round piece of wood 205 years after it was installed on an ox cart, consider that the log it was cut from may have been 100 years old to get this big around and it's possible that the wood is over 300 years old.
If it had caught on, we'd still know about it, but it is a interesting idea for rough terrain, maybe rocky terrain. Reminds me immediately of these other two unusual ideas in rim/wheel design http://justacarguy.blogspot.com/2011/03/justacargal-found-most-unusual.html
