Originally Posted by n4zou
Alloy from recycled engine and transmission blocks. If the manufacturer uses recycled material for the production of parts where a good finish is required the parts will be painted with a high quality epoxy paint, power coated, or lowest cost option dip coated in plastic. They also plastic coat steel to hid it's use.
Interesting, that makes sense. Thanks.
Originally Posted by robo
Cranks that look like that that i've seen have always been steel encased in plastic. I imagine if they were alloy with an additional plastic casing, they would be somewhat bulkier anyway.
Good point - although old-school aluminum cranks were pretty svelte (and probably flexy). See
this picture (what's not on my fixie). But those were still thicker profile (as viewed from above) than steel underneath the plastic in your cranks would be, so point stands.