Crank Bros Cobalt Cranks I guess it was inevitable that Crank Bros should make a crank. But rather than heading out to paint their name on a bog-standard unit, they've really gone to town on the design. For a start, it's a composite crank, hollow and made from two very different materials. Under the skin is a forged aluminium skeleton to which is bolted the two halves of the outer skin - made from shiny, shiny stainless steel, which is then fused to form a single box shape around the skeleton. Replaceable steel inserts then take care of the pedal threads. I didn't get a chance to weigh it, but the parts themselves were individually light and together should form a strong box section. We've not seen a crank this interesting since Shimano's new XTR (actually, probably since Magic Motorcycle's crank...) - the only talking point, though, is that it's currently only available in ISIS drive - at a time when Race Face and Truvative seem to be moving away from it.