Cable housing info

Some of us cyclists like to do our own bicycle tune-ups and parts replacement. One part that often gets overlooked is cable housing. We might even be very conscientious about replacing the cables themselves each season whenever we feel like there is sluggishness shifting or a little extra effort in order to brake. This is a good thing. But how often do we replace the housing?

It’s a pain to replace, you have to unwrap your bar tape. You may have to loosen or dismount brake levers. There may be some electrical or other pieces of tape holding the housing tight to the handlebars that has to be removed. Whatever the reason, it is not something we really pay much attention to.

Any time you see wear on the plastic housing cover so that any of the underlying metal shows, a tear in the housing cover or a kink in the housing you should think about replacing the housing. If you want to give your bike a whole new look and feel replace the OEM black or gray housing with some color. You will be surprised at the difference.

So now that I am going to replace the housing, what should I know about them. Well, one thing to note is that you will see two types of cable at your local bike shop. They are labeled Derailleur and Brake. They are different, and are not 100% interchangeable.

The following two diagrams (courtesy of Alligator Cable Systems) shows the typical makeup of both these types of cables. The first image is typical derailleur cable housing. Notice that the housing is built up as follows: Jacket, usually made of colored plastic. Strand wire that runs the entire length of the cable, this wire makes the cable very flexible yet at the same time allows it not to compress against the tension in the cable itself. This feature is important for the precision of multi-speed indexed shifting systems. Then there is a liner, usually made of polyethylene that allows the cable to ride smoothly within the housing.

This second diagram is of typical brake cable housing. Again note the following characteristics: The same colored jacket. A coiled flattened steel wire replaces the strand wire, this coil is actually stronger than the strand wire and can withstand the tension applied the usually thicker brake cables when applying brakes during cycling. A by product of having to make the housing stronger is that it become less flexible (the one loop from the rear derailleur cable stop to the derailleur itself is harder to make if you use brake cable housing). Then there is the same liner.

One more note. You can use brake cable housing for both braking and shifting systems but you should never use derailleur cable housing on braking systems.

So the next time you think about changing the look and feel of your ride, do not overlook cable housing. Your local bike shop will most likely have standard black and gray cables in bulk lengths that they can cut for you to any desired length you want or they will have brake, derailleur or complete cabling kits with all the necessary parts.

Although people pay a lot of attention to what kind of derailleurs and brakes are fitted to their bicycle, good cabling is more important than most differences between different brake and shift systems. The most expensive brakes and derailleurs will work poorly if there is excessive friction or play in their cables. Even the cheapest brakes and derailleurs can usually be made to perform satisfactorily if care is used in installing the cables.

The great majority of service problems with brakes and shifting are the result of cable friction, not deficiencies in the levers, brake calipers or derailleurs. Look for a future article on cables.