If you are looking for the best strength-to-weight crank, try Specialized S-Works Road Crank Arm. This third generation hollow carbon crank arm is stiff with its oversized alloy spindle, self-adjusting oversized 42 mm cartridge bearings, and new unidirectional carbon fiber finish. It also includes all hardware and is compatible with BB30 and specialized road frames with an oversized bottom bracket shell.
The Specialized S-Works Road Crank Arm is available at the lengths of 167.5, 170, 172.5, 175, 177.5, 180 mm, all at $250.00. Take note, however, that these crank length variations are insignificant. It is not a problem with average sized cyclists. But for tall cyclists, a crank that is 185 mm or longer is recommended. At the moment, there are a limited number of long cranks on the market.