Why are steep hills so... not steep? A 10% hill is supposedly very steep for cars, and even tougher for cyclists. But you're only going up 10 meters for every 100 meters you travel. That is not steep at all when you plot it on a 2d surface. I would say something like 30% is steep. But some say even 4% is steep for cycling, which is just ridiculous. Going up 4 meters in a 100 meter span is hardly even noticeable to the eye.