"My bike is mostly all stock except for the cranks, which I customized to ultra-short 153 mm cranks with a lower-geared chain rings Best decision I ever made, as I am a very short person (5'2) and these cranks are at least 5x more comfortable and usable than my old 170s, no kidding. Although I do wish I had bigger gears (the stock chain rings had slightly higher gearing than what I have now)."

The '14 Trek supposedly comes with a Shimano Acera M391 crank. However the images of the crank "arms" that I see online are different from the arms that came with my bike. My "arms" seem rather long, being 5'6" does this prevent me from pedaling faster, reduce cadence, etc?

Attached is a photo.