Sidi has a little bit of a different idea as to what makes a good shoe. Nike and Shimano make a carbon sole that is WAY stiff. More efficient for pushing they say. Sidi figures that your foot's gonna give anyway, so why not make the shoe more flexible instead...Field said:The soles of the genius 4 feel awfully soft when flexing with my hands. Looking specifically for a racing shoe and want to make sure they aren't too noodley before i buy. Also, anyone use sidis with the carbon sole? Are they uncomfortably stiff?