Hmm. Fair point about the tangent. I've also just done some force diagrams (for the first time in a couple of decades) and decided the downforce on the wheel's contact patch with the pavement will also remain good.

On the other hand, the degree of poise and balance required to hold a unicycle or similar thing steady at such a great angle will still surely be infeasible? Especially when the vehicle hits even the tiniest bump in the road while braking?