Housing length for a set will obviously depend on the set, but if you measure your current housing lengths, and add the lengths of the exposed cable sections, you will arrive at the neccessary length you need.HuffyMan said:
HOWEVER, it has been my time tested experience (almost 10 years as a pro mechanic) that the name brand or price of your chosen cable/housing is about 10% as important as the preparation and proper installation of your choice. For housing ends, file or lightly grind the end of the housing so that it is TOTALLY SQUARE WITH NO BURRS. After doing so, ream it with a sharpened spoke to make sure that the inner plastic lining has not melted or pinched closed (I prefer a spoke over an awl because the full 1.8 or 2.0 mm cross section will go more fully into the housing than just the tip of your garden variety awl). After reaming, LUBE YOUR HOUSING. You will like a full on grease if your area is muddy and wet or particularly dusty. If you ride in pristine conditions, injecting triflow into the housing will make your brake/shift action much lighter and smoother. If you use ferrules on your housing ends, don't worry about crimping them on (sometimes you can overcrimp and deform the housing, or the crimping action will cause the housing end to migrate slightly from the inside stop of the ferrule. Use a good quality stainless steel slick cable (Teflon coated black or regular, whatever tickles your pickle). Lace it through, snug your anchor bolt and prestretch it by pulling the brake lever with both hands really hard for about 5-10 secs. After that, you can proceed with your normal set up and adjustment procedures. You will find that if you take the time and set it up right the first time, you won't have to constantly back out your barrel adjusters due to cable stretch, nor will you have to deal with the brakes feeling like crap right after set up or after just a few rides due to gunk fouling things up.