Your brake and gear cables will eventually need changing, this is a job you can take to the local bike shop, but you could do it your self, save some money and learn a bit more about your bike.

First have a look at your cable, has it broken? That one is easy. If the cable is rusty or if it has frayed change it, it might snap and if you are descending a long or steep hill and your brake cable snaps you’re going to be in trouble.
If the cable is not running smoothly you can take it out grease it and put it back, this is just like fitting a new cable, but cheaper.

Gear or brake?

Brake cables are a little thicker than gear cables, on the end of all cables there is a “nipple” this is the lump on the end that locates into the gear or brake lever, so it can be pulled.

Nipples for brake cables are different for road and mountain bikes, for road it’s a pear shape and for mountain bike its like a barrel, gear cables are also like a barrel, but smaller and are either the cable comes out of the top or the middle of the barrel.

The good news is that most cables you buy have the different nipples on either end, so you can cut off the one you don’t need.

Tools you need

1. Small screwdriver.
2. 5mm Allen key.
3. A good pair of cable cutters or pliers.
4. Oil & grease
5. With older brakes and gears you may need an 8 or 10mm spanner.

Brakes First

Road and mountain bike brakes are nearly the same when it comes to changing the cable, first loosen the cable clamp bolt and pull out the cable from the lever, paying attention to where the cable runs as the new cable will be in the same place as the old one.

To do a very good job, pour or spray some oil into the cable outer and put some grease on the cable before you feed it back into the outer cable.

First cut off the nipple you don’t need, and then locate the nipple into the lever, then feed the cable through the lever and into the outer cable, pushing it through until it comes out the other end, this could be at the end of the outer cable at the brake or where the cable is open on the frame.

Feed the cable through the rest of the outer cable to the brake, on a mountain bike with “V brakes” you need to push the cable through a “V brake pipe” and then into the cable clamp, pull the cable tight holding the brake blocks to the wheel rim and tighten the clamp on the cable.

Pull the lever a few times to stretch the new cable, then re-tighten the cable, cut the cable to leave about an inch of cable extra from the clamp and if you have a cable tidy (a small metal cylinder to go on the end of the cable) squash this on with pliers or the cable cutters.

Now the Gears

Basically this is the same as the brake cable, loosen the clamp bolt and push the old cable out, looking for where the nipple comes out of the gear lever, normally the gear lever has to be in highest gear to allow this, this is where you are going to push the new cable in.

As with brake cables cut off the nipple you don’t need, oil the outer cable and grease the inner cable and start to feed it through the outer cable till it comes out the other end or across a bare cable gap, until you get to the gear mechanism.

pull the cable tight and tighten the clamp bolt onto the cable, cut the cable about an inch from the clamp and fit a cable tidy if you have one.

If it is a new cable it will stretch, so you will have to adjust your gear mechanism again later, following the instructions for the article:

“how to adjust your gears”

and you’ll be OK.

Read more questions/answers about Breaking Gear Cables here!