Given the SL-K Light Compact EVO 386's high-quality ceramic bearings, meticulously plotted carbon construction, knee-saving compact rings, and classic five bolt aesthetics, you'll want to ride this FSA crankset forever. Happily, the EVO 386 promises to live up to its hype as the last evolution of the BB standard. Think of BB386 as a series of adapters that plug into the most common versions of bottom brackets in order to accommodate EVO386 cranks. Like its K-Force relatives, the SL-K's crank arms are molded around two tubular bladders, so the structure is buttressed-up with a thin, central sheet of material that runs the length of the crank. The cross section resembles a peanut, and the result is a lightweight crank arm that doesn't skimp on power transfer. This power transfer is further complemented by the SL-K's impossibly smooth and durable ceramic bearings. Ceramic can withstand even industrial applications without flinching, so for a bicycle, they're the bearing equivalent of spinning up on clouds. The wider, 86 millimeter spacing pushes the contact point with the pedals out slightly. Since the bottom bracket extends further, the crank arms don't have to bend as much to provide ankle clearance on the frame. That means less material, so it saves grams, and higher torsional stiffness because the crank arm itself is straighter. You know how bowed seat stays provide compliance to absorb road impact? The same is true of bowed crank arms, but the extra compliance works against you by flexing, which hampers efficient power transfer. Given the flexibility of BB386, the SL-K Light cranks are future-proof. They'll travel with you from frame to frame, and -- by installing your choice of FSA chainrings designed to work with Shimano, SRAM, or Campagnolo -- drivetrain to drivetrain. The compact chain rings may also help future-proof your knees, providing some relief on grades in the high teens and twenties in case you live in a geography like our home base in Utah.