Thank you for your very thorough response; it's very helpful! But how do I decide which shifters/derailleurs/crankset and all that stuff to get? Like why do you use two different types of derailleurs (The tiagra and LX) for front and back? And how do you decide what size to get for the crankset (such as the 175mm) I just basically need a whole guide on what shifters/derailleurs/cranksets are best for what haha