You may find when you’re replacing the brake inner cable that it feels gritty as you feed it through the first section of outer casing – this runs from the brakelever under the bar tape to the frame, in the case of the back brake, or directly to the front brake unit. If this is the case, you will need to peel back the bar tape and replace the outer casing as well as the inner cable. It’s an irritating job, but will make your brakes feel much crisper and more responsive.
There are other circumstances in which you might want to replace the first section of outer casing. You may want to raise the bars and find that the casing isn’t long enough to do so without forcing it around tight bends. You may also have found damaged or kinked spots in the casing.
Either way you’ll need to get some fresh bar tape before you start. It is possible to reuse the old stuff, but it’s sticky-backed so doesn’t often come off without tearing and tends to refuse to lie flat when you wind it back on again. Treat yourself to new tape – it makes your bike look much smarter too.
Best results come from changing the whole lot at once. Peel off the old stuff gently. You’re trying to lift off as much of the sticky glue as you can as you go along. Remove the bar-end plugs. Clean up the bars as best you can, but take care not to scratch the bars as small scratches can form the roots of cracks in the material.
Now you’re free to work on the brake cable and casing. You’ll have to tug the old brake casing out from inside the back of the brake levers. Look carefully to see if the cable finishes in a ferrule – if it does you’ll need to remember to refit the new casing with a ferrule.
Measure up the new casing and then cut it carefully to length, making sure that the cut end is a clean cut and that there isn’t a tag of metal cutting across the hole through the middle of the casing. Replace any other sections if necessary and feed the inner cable through the middle. Pull through any slack in the cable, clamp it under the cable pinch bolt and pull the lever firmly to settle the new outer casing into place. You may find after this that you have a fair bit of slack. Loosen the calliper cable pinch bolt again, pull through more slack and tighten the bolt firmly.
It may be a little bit of a struggle to get the new outer casing to sit properly into the brake lever. It can help to loosen the bolt that clamps the brake lever onto the handlebars in order to give the casing a little bit of space. The bolt may be in one of two places. Pull the lever towards the bars and look into it from in front. You may see the head of an Allen key bolt at the back – often a 5mm. You should be able to wiggle an Allen key in there.
If the fixing bolt isn’t inside the lever, it will probably be on the side of the lever, under the rubber lever cover. Again, it will usually be a 5mm Allen key and will be on the outer side of the lever (the right-hand side of the right lever and the left-hand side of the left lever). Loosen the fixing bolt, wiggle the brake casing home and then retighten the fixing bolt firmly.
Tape the brake casing onto the front of the bars with three strips of electrical tape to hold it neatly in place. Three strips of tape on either side should do the job.
Once you’ve got everything taped together it’s time to refit bar tape. Start by filling in behind the brake levers. This is always too wide a gap for the bar tape to cross without leaving gaps. Your new pack of bar tape may have come with a couple of extra short strips. If not, cut two strips about 7cm (23/4 in) long off the end of the bar tape. Fold back the rubber brake lever hoods so they’re out of the way and wrap a horizontal strip around the bar from one side to the other. Leave the brake hoods out of the way. Start at the bottom end of the handlebar. Start with a strip of tape facing down on the inside of the bar with about half the width of the tape overlapping the end of the bar. Wrap so that each new layer overlaps a third of the last layer. When you get to the brake lever, wrap up to the short strip you already put there and then head diagonally upwards in one layer. Don’t be tempted to weave the tape back down again as you’ll just make the bar feel really bulky behind the brake lever. Once you get above the brake lever, carry right on up towards the middle of the bar – you’ll need to finish about 5cm (2 in) from the stem. Cut off the tape so that it finishes underneath the bar and then tape neatly in place with black electrical tape. Bar tape sometimes comes with little plastic grip ties, but they’re more fiddly than they’re worth and a layer of tape does the job better.
If you’ve been careful with wrapping the tape around the bottom section of the bars, you may find there’s enough to increase the overlap on the top section. This makes the bars more comfortable when you’re sitting in a more upright position. Fold the end of the tape into the ends of the bars, and refit the barend plugs. As well as keeping the ends of the bars neat, the plugs protect you from cutting yourself on the end of the bar in case of a spill.
“Treat yourself to new tape – it makes your bike look much smarter”
Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES