Why do brake cables come out of barrel adjuster when they are loose?

Question

My brake cable got unattached from the pinch bolt and came loose. I then noticed that at the other end the cable housing was not inside the barrel adjuster anymore. I thought something broke at the barrel adjuster but after reattaching to the pinch bolt the cable housing got properly inside the barrel adjuster. How is this possible? A simple mind would expect the cable housing to move away from the barrel adjuster even more when the cable housing is tightened.

Answer 1

What you have observed is what should be expected.

When there is no tension in the cable, then there would be no tension in the cable-housing and the housing ends would come off easily from the cable stop or barrel adjuster.

The housing ends sit in place inside the barrel adjuster when under cable tension.

The housing, like the cable, is flexible but it will not compress, it's engineered that way, this is by design.

When the cable is under tension, it will naturally straighten out into a line and because is running inside the housing, the housing will follow the cable's natural reaction to tension and try to straighten out too.

As the housing tries to straighten out into a line, the distance between the ends would increase, having the same effect as pushing one end into the barrel adjuster and pushing the other end into a cable stop.

Because the cable is in continues tension, the housing ends will also be continuously pushing their ends apart and stay put in place.

Take note that because the cable housing cannot be compressed, the cable tension is constant, until one end of the cable is actuated by a lever.

The more I observe the close relationship between the cable and the housing, the clearer it becomes to me the ingenuity of this setup.