Road bike brake blocks won’t be as sharp as V-brakes or disc brakes even when new, so make sure your cables are in good condition for the best possible braking.
The back brake in particular has a long cable, and both cables are routed under the bar tape, so they’re forced around tight turns. Once the cables start to deteriorate, you’ll find that the levers become steadily harder to pull, and the brake blocks don’t spring easily back from the rims once you release the levers. Replacing the cable makes a massive difference If the outer casing is kinked or damaged, it should be replaced at the same time as the cable. Use the old sections to measure out new sections, taking care to cut the ends clean and square. New bits of casing need a ferrule at each end of each section. The exception is the last one, where the casing enters the calliper. There may not be room for a ferrule, in which case it doesn’t need one.
Step 1 : Make sure you have the right kind of brake cable before you start – road bikes use a different type from the ubiquitous mountain bike with a pear-shaped nipple on the end rather than a barrel-shaped nipple. Once armed with the correct type, cut the cable end off your old brake cable. You’ll need a decent pair of cable cutters a pair of pliers isn’t good enough as you’ll just end up fraying the cable.
Step 2 : Feed the brake cable back up through the outer casing. You can leave this in place, but check each piece as you pass it through since sections that are kinked or crushed, or have patches of the protective plastic coating missing, will need to be replaced. If the cable feels gritty as you remove it, it’s also worth replacing the casing.
Step 3 : When you get up to the handlebars, you’ll have to pull the lever back to expose its innards. Push the cable through the casing from the other end. You should see it emerging gently from the lever. Keep pushing though until a handful has emerged, then pull the whole lot out. Watch as you extract the last bit of cable so that you can clearly see the nest where the new cable has to go into.
Step 4 : Now the tricky bit: getting the new cable back into the lever. Success depends on having a neat, non-frayed end on your new cable. Keep the brake-lever pulled back against the bars and feed the cable back into the nest in the brakelever. Once it’s through the nest, feel for the hole in the back of the brake-lever. You should be able to see the brake casing under the bar tape, which will give you an idea what you’re aiming for. Feed through.
Step 5 : Once the cable emerges from the outer casing, pull it through until only the last 10cm (4 in) of cable sticks out of the lever. Keeping the brake-lever against the bars, drip a drop of oil onto this last bit and pull through completely. For the front brake, the cable goes directly into the front brake. Ensure as you route the back brake that there is enough slack in the outer casing for the handlebars to turn freely. Oil the cable as it
passes through the outer casing.
Step 6 : On the brake calliper, pass the cable through the barrel-adjuster. Set this so it’s about halfway through its travel. Check the cable pinch bolt there will be a clear groove where the cable rests. Sit the cable in place and squeeze the brake blocks against the rim. Pull through the cable to take up slack. Release the cable, keeping the blocks against the rim, and tighten the cable pinch bolt.