Brakes can be separated into two distinct categories. Rim Brakes & Disc Brakes. In this part, we are looking at rim brakes.
You can see above that there are 3 different types of rim brakes, however they all work on the same principle. There is a pivot point, spring mechanism and a cable connected to a lever. When the lever is pulled, it tensions the brake and applies the pads on the rim. Then when the cable is released the spring mechanism releases the pads from the rim back into their ‘off’ position. So, for this manual we will be looking at Cantilever brakes but would recommend you purchase a book that covers all the various types.
Cable Maintenance
- If the cable is frayed or kinked or has any broken strands, replace it.
- If the cable is not sliding well, lubricate it.
You’ll need a new brake cable. You should check this is the same as your current brake cable with the same nipple style on the end. This will vary depending on the type of brakes you have. You’ll also need the cable outer casing if you intend on replacing it, as well as metal ferrules, an end cap and a wire cutter
Before you remove the brake cable, look at how it is currently threaded around your bike. This will vary between different bikes. If you don’t have very good memory, then take pictures of the way it is threaded so you can repeat this once it is removed. Using an Allen key undo the clamp bolt that holds the brake cable in place.
Turn the barrel adjuster and line it up so that the cable can be threaded through, and ease out the cable. You will need to pull the brake lever to expose the nest where the cable nipple is held. Pull out the old cable and keep all the parts.
Check the outer casing to see if it has any kinks. If it does then this will need replacing otherwise you can use the existing casing, unless it is very old, then it is worth replacing anyway. If you are using new outer casing, then cut it to the same length as the existing one. If you don’t already have outer casing you will need to estimate the length that is needed. This can be tricky, so it may be worth getting advice from an expert.
If the outer casing is too long, then the braking will not be efficient. Use good quality wire cutters to be sure the ends of the outer casing are cut square. Often you will need a pick to clear the opening as this can get squashed when you cut them to the correct length. If you are replacing the casing, then attach metal ferrules to the end of it. Depending on the bike, you may not need to attach a ferrule on the end nearest the brake unit. It’s a good idea to drop a little bit of lubricant into the ferrules to keep everything working well.
If the new brake cable you have bought has two types of nipple attached to either end choose the one that matches the type you have already. Apply a very thin layer of chain oil to the cable using your fingers or a cloth. Do not use grease as this will thicken over time. This is just to prevent rust and only a tiny amount is needed. Then thread the cable through outer casing.
Then hook it back onto the brake lever, starting at the nipple. To do this, pull the lever and slide the nipple into the nest. Thread the cable through the brake lever and through the barrel adjuster. Then turn the barrel adjuster so that the cable cannot escape. Slide the outer casing into the barrel adjuster. On the other side of the cable, you will want to put the metal noodle back on. Also, the rubber will need sliding back on. This should be done with the large side first.
Thread it through the cable clamp bolt, then tighten the bolt loosely just to hold it in place for now. Then reconnect the brake with the arm that holds it in place. You can then make any further adjustments you need to do by undoing the cable clamp bolt and pulling the wire through.
Now it’s time to test your new brake cable. Pull the lever down hard twice. When you pull your brake lever halfway the brakes should be fully engaged. If this does not happen then you need to adjust the cable from the cable clamp bolt, letting out or in a bit of cable. It is a good idea to start with the barrel adjuster fully tightened so that, then as the cable stretches and the brake pads wear, you can loosen it.
Double check all the bolts are firmly tightened and the wire end is tucked away. If you do have excess cable then cut this off using the wire cutters, leaving about 3-4 inches of cable for future adjustment. The cable should then have an end cap on it to prevent the wire splitting which should be fastened by pressing down on the open end. Test your brake out a few times to check everything is working okay.
New cables always stretch out after a bit of use, this is partly why new bikes come with a first free service. If your brakes start feeling a little spongy in a few weeks, you can adjust them at the barrel or the clamp, whichever you prefer.
