Chain and Cable Wear
Chain and cable wear are important basic concepts in bicycle maintenance. Mechanical wear on your bicycle means you will inevitably need to replace parts from time to time. Two of the items that most commonly need replacing are the chain and cables. With the chain in particular, a little preventive maintenance can save you money in replacing higher-cost components later on.
Wear on your chain occurs as a result of friction between the rollers and pins. This leads to a loss of material and a loose fit between the moving parts. A loose fit increases the effective spacing between links in the chain, as though the chain had stretched. The result is that the chain no longer meshes well with the sprockets. Poor meshing then causes reciprocal wear, especially on the rear cassette. If this goes on long enough, when you replace the chain, the new chain will not mesh with the old sprockets, resulting in skipping. You will then need to replace the cassette along with the chain, at a higher cost than replacing the chain alone at an earlier stage.
How do you know when to replace your chain? One of the simplest ways is to use a chain gauge (pictured below). By slipping the chain gauge between the links of the chain in different orientations, you will know whether the chain is worn above 0.75% or 1.0%. Typically, you should replace a chain when it shows above 0.75% wear. Depending on how often you ride, for example if you use your bike for commuting, you might reach this level of wear in 6 to 12 months.
A simple chain gauge, suitable for testing chain wear at the 0.75% or 1.0% level. When the tool slips easily between the links, the chain is worn to the indicated level.
Bicycle cables characteristically comprise an inner and outer component, with cable routing varying from one manufacturer and model to another. In some bikes, the cable inner is exposed over part of its length (pictured below), while other bikes encase the cable over its full length.
Over time, friction between the cable inner and the Teflon sleeve of the cable outer leads to formation of grooves that inhibit free movement of the cable inner. When this occurs, the cable tends to stick and you will have difficulty braking or changing gears. If you replace the cables, this low-cost maintenance step will have a marked effect on your riding enjoyment.
Different manufacturers and models often have different cable routing. With this model, some cable inners are exposed and the cable outer is capped to minimize entry of dirt or water.
Chain wear checks, chain replacement and new cable fitting are part of regular bicycle maintenance. They are important to keep your bike running smoothly. Bike Knack provides chain and cable wear maintenance, together with general bicycle service on road and mountain bikes, from our Salisbury workshop. You can find prices for labour in our Pricing Table, or you can reach Dave via the Contact page.