There are various reasons why you may need to replace your bike’s brake cable, but it’s usually because of wear or breakage. Bike brake cables are made of steel braids and are very resistant: there’s a metal terminal at one end, which can be spherical or barrel, which allows the cable to firmly connect to the brake lever. The cable is subjected to considerable stress and, sooner or later, may show signs of wear. The cables typically fray near the clamp that connects them to the brakes, or at the terminal, or they might fray or break along the path in the sheath. Another frequent problem is found in bikes that haven’t been used for months, whose brake cables and sheaths had not been adequately dried and lubricated at the time of storage. In these cases oxidation can occur inside the sheath: the cable slides poorly, the braking becomes “pasty” and the lever is hard to operate. In these situations, the cables must be replaced, and sometimes even their sheaths.
Bikes whose braking system is made of steel cables (and thus not hydraulic) can have three types of brakes:
This doesn’t entail particular differences from the point of view of replacing the bicycle brake cable, while the types of connections to the brake are different. The types of regulators near the lever or brake (or both) may also be different.
The first step is to loosen the brake clamp: in caliper or V-brake versions, the clamp is on the actual brake, while in the cantilever version it is “floating” and consists of the clamp plus the arch that receives a second cable that operates the two spring pads. Once the cable has been removed from the clamp, the brake lever can be moved and the terminal is exposed. By rotating the regulator on the lever and its locking ring so that their grooves are aligned, the cable part can be removed with the terminal and then the cable can be completely removed from the sheath.
After examining the sheath and making sure it doesn’t have any problems, you can insert the new cable. While doing so, we suggest applying a generous amount of WD-40 Specialist High Performance PTFE Lubricant along the cable, which provides excellent lubrication and protection by reducing the friction of the cable inside the sheath, and is ideal for components or mechanisms exposed to water.
When the cable is inserted into the sheath, place its part with the terminal in the appropriate seat of the brake lever and then rotate the regulator and its ring nut into a position so that their two grooves do not coincide, to prevent the brake cable from sticking out. Make sure to also position the sheath head against the lever and brake regulators.
The bicycle brake cable sticks out of the lower part of the sheath. Its end part (towards the brake) can have a curved metal tube that connects it to the brake itself so that the cable does not exert too much friction inside the sheath itself. The cable must be inserted into the brake clamp (previously loosened). Before tightening the clamp, the two pads must be tightened with each other, bringing them closer to the rim. Keeping the brake in this position, tighten the screw clamp, thereby locking the cable. After doing so, cut the cable 3-4 cm downstream of the clamp. Make sure to use a good cutter that cuts with a dry and precise stroke to avoid fraying the steel braid.
Insert the special metal end at the cut end of the cable, which must then be slightly deformed, tightening it with a clamp to prevent it from slipping. Once you have finished, check by rotating the suspended tyre (best with the bike on a support), checking both the braking and the distance of the pads from the rim. If necessary, adjust their positioning (different depending on the type of brake on the bike).
Finished replacing the brake cable on your bicycle , now make sure you test it before riding away in the sunset.
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