Kahlers are notorious for falling out of tune after abuse, not only for the roller issue, but also because they're only a single-locking design, and the strings are only held to the trem by their own tension. When you dive them, the strings can come loose from the claws that hold them, and when you return to pitch, they might not seat properly again. With my FR guitars, I usually don't have to retune after I record a track, but the Kahlers, I almost always do. I'm sure there's a way to rectify that, but honestly, I haven't put the effort into it to learn how, as my main players have Floyd Roses, and the Kahlers have been relegated to practice axes.
