Originally Posted by nhluhr

I could be wrong, but that looks remarkably like a crankset that was recalled by Shimano many years ago. These cranks were known to have defects that allowed them to crack easily, leading to the crank-arm sheering off under force.

Originally Posted by Bixid

The cranks have been installed on more than 200 models of bicycles manufactured since 1994 and sold under at least 49 brand names. Most bicycle manufacturers have sold bicycles that are involved in this recall. The cranks also may have been installed as an upgrade as part of the Altus, Acera and Alivio groups of components. The cranks are numbered FC-CT90, FC-M290 and FC-MC12. These numbers are located on the back or inner side of the right crank arm.

Consumers should check their bicycles' crank assemblies. If they are involved in this recall, consumers should stop using their bicycles immediately and call Shimano at 800-353-4719 to arrange for the free replacement and installation of a new crank assembly at a nearby authorized repair shop. Consumers can also arrange for the free replacement with their bicycle dealers.

Originally Posted by Feldman

Though ten years on [this post is dated 2007 - Kimmo], Shimano is still honoring this recall--they really, really want those cranks off the road. It may be fear of liability, but to this bike business lifer it's an example of a company that really does give several dozen damns about its customers.