The mass of this bike's frame sits insanely low in the cockpit, around your shins, for BMX-quick handling. Our test model weighed slightly more than 23 pounds, thus making short work of uphills. And thanks to a supertight wheelbase, cornering is instantaneous – but be warned: You can overcook curves if you're not on your game. That right-now reaction time is the result of an ultrastiff, unforgiving carbon chassis, so while you'll blow past other riders in mud and rough terrain, your spine will feel the lack of rear suspension. [$3,400; yeticycles.com]