Yesterday, I tried a shortcut on my way home from work. It's a short, not terribly steep, rather even path that would be no problem with an ordinary mountain bike. But recumbent trikes - and the Quest family of velomobiles particularly - don't have enough weight on the back wheel and lose traction easily on gravelly inclines. On top of that, my rear tire was completely slick. Not exactly the most ideal setup to ride up that shortcut :)