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Monday, February 16, 2009

Is this dangerous?



Rotor's prototype crankset is hollow and drilled full of holes
Photo ©: James Huang

A closer look at Carlos Sastre's Rotor prototype cranks

Recently we gave you a quick look at Carlos Sastre's (Cervélo Test Team) prototype Rotor cranks but information on them was decidedly scarce at the time. Though they appeared to be hollow-forged cranks with a smattering of holes drilled in them to save weight, it turns out that we were only partially correct. The crankarms are indeed hollow and forged and the holes do save weight, but the order of operations is not what you would expect and is what makes these special.

The arms actually start out as solid forgings, not hollow ones. Holes are then drilled clean through the arms from both the sides and outer faces but their diameters, directions and locations are carefully selected such that the overlapping intersections leave virtually zero material in the crank interior. The result is effectively a hollow-forged part with a liberally perforated skin plus an indisputably distinctive appearance.

It remains to be seen how well the novel cranks actually perform but regardless, the concept is ingeniously original. In fact, not only does it apparently avoid infringing on anyone else's patents but Rotor has filed one of its own.

Rotor insists that Sastre's crank is still only a development mule, however, and though the manufacturing process has a name the item itself still does not. In fact, Rotor co-founder Pablo Carrasco said that the 2008 Tour de France champion won't even be using it in competition here at the Tour of California.

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