Given that these have a round core, in my personal experience, they stay in tune even better than hex core strings. I use GHS fast fret on my strings after i play, and wipe them down very aggressively. Even after pulling them as hard as i can with the cleaning cloth, they are still in tune the next time i pick up the guitar. (non locking hipshop hard tail bridge). After initial stretching these strings are solid as they get, in my experience.