The last big breakthrough in mountain biking was the creation of 29-inch wheels – bikes equipped with them, while slow and unwieldy, could pancake everything in their path, and made newer riders confident enough to saddle up and take on steep, rocky downhills. Now there's a new sweet spot: the 27.5-inch wheel. These have plenty of leverage over roots and rocks, but are lighter and have a shorter wheelbase than 29-ers. This means riders can be more playful with them, and so can mountain-bike manufacturers, who are changing geometry to accommodate nimbler, easier training. We pedaled hard to find the best of this new breed.
The Cross-Country Rider: Jamis Dragon 650 Pro
Like the Yeti, the Dragon is a hardtail, meaning it has no rear suspension. Unlike the carbon Yeti, though, it's made of steel. Sure, that adds about three additional pounds and makes climbing more strenuous, but the bike overall is more forgiving and flexible. Its low-set sitting position and short wheelbase yield smooth – if not hyperactive – cornering. And despite its 26-pound-plus frame, this rig is spec'd with light wheels that reward getting on the throttle: Its all-out acceleration is actually on par with more expensive rigs. [$3,000; jamisbikes.com]