Take a typical forest track or riverbank, or any other piece of rough trail. It will present a number of obstacles such as sudden bumps or hollows, tree roots, puddles, patches of mud and so on.
On a Coker, I will tend to take a fairly direct route, or even go looking for the obstacles to make the ride more interesting. Generally, the idea is to keep the speed reasonably high (but with a bit in reserve) and to use momentum and the size of the wheel to carry me over the obstacles. This means I have to make few concessions to the trail - I just “hack at it”.
On the 28, with its narrow higher pressure road tyre, complete lack of grip, tiny momentum, and the short cranks, this approach would soon lead to me falling off. Every sudden bump could trip me; every sudden dip could become a wheel trap; every patch of mud or slime could cause a side slip.
Suddenly, the trail looks very different. Instead of it being an uneven surface to be crossed, it becomes a maze of small obstacles to be avoided, or selected. My exact choice of route becomes critical. If I go to the left of this puddle, will I be in a good position to get past that deep rut? Should I ride the edge of the rut, or drop into it? If I do, how will I get out of it? What’s the best way round that tree root?
On the 28, the trail becomes a puzzle to be solved. I have to think ahead, avoid being trapped in a blind alley. Small changes in height matter - even a few inches of gravity karma gained here could carry me past the obstacle 10 metres further on.
I use the fencing metaphor because I do fencing. I can see huge similarities between cross country unicycling and fencing, and these similarities are more obvious on the 28 than the Coker.
I’m not saying it’s for everybody, or even that I would like all my riding to be like this. However, there is a lot to be said for selecting a unicycle that adds value to what might otherwise be an easy and boring trail.