i just installed new brake cables on 2 bikes. (switched from DA cables to yokozunas, a stiff brake cable.) one is da79xx and the other (the now spongy one) is da 7800.
for the 79xx build, i could not use yokozuna's oversized ferrules where the cables connect to the brakes (cable adjusting bolt); in fact, i could not use any ferrule as the fit was VERY snug. braking is phenomenal.
i didn't use ferrules for the da 7800 build either. the inner diameter of cable adjusting bolt seemed even narrower; i had to trim ~8mm of the cable jacket (including the steel spiral) to even get it to fit into the connection with the brake. the individual longitudinal strands of the housing are intact. braking with the 7800's was just fine before with the DA cable/housing, but the cables were old and needed replacing.
i used a dremel and made excellent cuts across the board.
the issue i have is slow return. the first time squeezing the 7800 lever feels great, but once i let up the cable doesn't seem to fully return such that the first cm of lever travel on subsequent occasions is totally soft before the cable bites. note: the lever itself returns just fine when i let go, but it feels as if the cable does not.
i've taken up all slack, but it doesn't make any difference in the 2nd and subsequent pulls of the lever.
could i have cut the housing too short, perhaps?
could the issue lie in cutting back ~8mm of cable jacket on the da 7800 build?
could the issue be too tight a bend in the cable? (it's no tighter than on the di2 build, so i doubt this.)
i'm open to any suggestions, but i've reached an impasse here, at least for tonight (it's 1:30 am).
thanks so much for any ideas!