crank bros including the quatro work with mtn and sport shoes, if you get the spd sl then you have to get new shoes, road shoes. The road style shoes/pedals have no tred on em, and the plastic cleat sticks out so its really hard to walk. With mtn shoes u can walk, but they arn't as stiff, personally i've never felt like my quatros aren't stiff enough, and they are super easy to use,