hmmm, I am not that educated on cranksets and gear inches and all that mumbo jumbo. But logically speaking when you take away that small ring you basically take away the easiest gears you can have, simply meaning when you go up a mountain you cant rely on your small gears to get you up, so your going to mash on that 39. Thats the way I see it, but I am not an expert. Thats why I rather have a triple.