As its name might suggest, Shimano intends the XTR FC M9020 2 2x Trail Crankset for off road cyclists who require beefy gear because they literally hit the trail when they hit the trail. It's a built up version of Shimano's Race crankset, made to stay stiff and sturdy when you're riding the ragged edge on trail furniture island. The Trail cranks aren't a step down, efficiency wise. They're underwritten by the same HollowTech II crank arm technology, they're just not quite as hollow as the Race models. The chainrings also have chain retaining titanium teeth with shifting paths and ramps designed to facilitate the precise shifting you expect from XTR.