SRAM's one by drivetrain revolution may be the highlight of the mountain bike tech coming out of the innovative manufacturer's Illinois headquarters, but the X01 GXP Direct Mount Crankset may be a close second place. The X01 Direct Mount cranks effectively eliminate the spider for an interface that saves weight and is easily altered to make the most of your one by setup across all terrain types. And while that pre ride versatility is a nice touch, it doesn't necessarily provide much solace when you're gasping in disbelief at your cranks on a steep climb when you're struggling just to turn over your granny gear. That's when you'll appreciate SRAM's efficiently stiff, lightweight carbon crank arms, which are the exact same as the arms featured on the XX1 model. The only difference between the X01 and its more expensive counterpart are subtle areas of machining on the chainring of the latter. The chainring itself features X Sync's tall, square teeth to engage the chain sooner on each rotation for maximum control so the chain doesn't get bored and wander off onto your pedal spindle. The teeth also alternate between narrow and wide with mud clearing recesses in between in order to keep a hold on the chain even during deflections on mucky trails. It's finished with a built in forged aluminum spider that sticks to the lightweight theme while carefully preserving the carbon crank arms' gains in efficiency.