Review on Enhance Your Road Cycling Performance with the Shimano Road Gear Cable Set - Steel by Dan Cramer

As others have said these cases are spiral wound which allows them to give some. After many adjustments, my shifting on the rear derailleur was worse than before the housing and cable change. If I adjust it so that the cassette downshifts perfectly, it doesn't shift up properly. I have to squeeze the lever a little more to raise it to the next gear, right on the bottom of the cassette. It's hard to explain, but when you shift into higher gears you can feel some flexing in the cable housing. I crank them up and buy a Jagwire, which is what I should have done from the start. It just sucks because I also have to rip off and replace the tape on the handlebars. Update: I installed Jagwire cables and with very little adjustment, shifting is as smooth as it should be.