Brake Cables

(M = mountain bike; R = road bike; C = cruiser)

DESCRIPTION: (M, R) The brake cable runs from a notch or hole in the hand lever, through an end ferrule or an adjust able sleeve, which fits or screws into the brake lever post, then through a cable housing (which is sometimes interrupted so that the cable runs bare next to a frame tube), an other end ferrule, and finally, through a carrier and/or an anchor bolt that holds the cable at its mechanism end. (See Info-graphics 2-1, 2-5, 2-8, and 2-10.)

Info-graphic Brake Cable and Ends

PROBLEMS: (M, R) Brakes loose. Imagine this: You are screaming down Kamikaze at Mammoth and you come flying around a blind curve just a wee bit too fast, and suddenly you find yourself heading for a bathtub-size boulder. You slam on the brakes. Nothing happens for a terribly long instant. The next thing you realize is that the ground is coming up at you.

Arrgh. To avoid this type of nightmare, keep your brakes adjusted.

(M, R) Adjusting the brakes usually means tightening the cable. How tight is tight enough? Most shops do brakes so you only have to squeeze the lever about halfway to the handlebars to apply them fully. Some people (and I’m one of them) like their brakes a bit looser than this, so the lever goes most of the way to the handlebar before the brakes are fully applied. This makes sense, because it lets you grip the bars with most of your fingers while applying the brakes with just two slightly extended fingers. Short, “two-finger” brake hand levers are good for the same reason, as long as they give you enough leverage. But no matter what your brake setup, you should never let either brake get so loose that the handle goes all the way to the handlebar without stopping the wheel.

(M, R) Minor adjustment will usually be enough to get you home. See if there is an adjusting sleeve on your brake handle. On most road bikes the adjusting sleeve is at the mechanism end of the cable. You can adjust these sleeves by hand, unless they are mud-clogged or rusted tight. Loosen the lockring and then turn the sleeve counter clockwise too, even though this may not seem right to you at first. It tightens the cable, because it has the effect of making the cable housing longer, which tightens up the brakes. After adjusting the sleeve, try out the brake. If it works OK now, tighten the lockring hard against the hand lever or brake mechanism (not against the adjusting sleeve) and you’re ready to go. If it’s hard to tighten up the cable, try squeezing the brake shoes in against the rim with one hand while you use the other hand to fiddle with the adjusting sleeve; taking the tension off the cable often makes it easier to tighten the brakes. If you cannot get the cable tight enough even by turning the adjusting sleeve all the way out , you have to do a major adjustment with the cable anchor bolt. Turn the sleeve back in until it is at least half way to its loosest setting, then tighten the lockring against the hand lever or mechanism and go on to the next paragraph.

Info-graphic 2-6 Adjusting Sleeve

(M, R) A major brake adjustment is hard to do on the trail or road if you don’t have two wrenches, or at least a wrench and a good pair of pliers, along with a friend who’s willing to lend a strong hand or two so you can loosen and tighten the cable anchor bolt. Look at Figs 2-8 and 2-10 to see where the anchor bolt is on your brake mechanism. Most mechanisms have the anchor bolt on one end of a cantilever or brake arm. On many mountain bikes, there is also a secondary anchor bolt that pinches the cable at the carrier, as in Figure 2-8.

(M, R) Before tightening the cable, see if you can loosen the brake. On mountain bikes, undo one end of the short transverse cable from its socket in the cantilever. On road bikes, pull the release lever on the mechanism down, so it loosens the cable.

(M, R) Then get a wrench or the pliers fitted tight on the head of the anchor bolt. If you have a friend to hold the wrench or pliers on there good and tight, it makes the job a lot easier. While the anchor bolt is held still, loosen the nut until the cable can slide through the anchor bolt. Then move the anchor bolt up the cable about a quarter of an inch (the anchor bolt is about a quarter-inch thick, to give you an idea). You can gauge how far you are moving it by looking at the squished-flat section of the cable where the anchor bolt used to be. When you have moved the anchor bolt up (that is, you have pulled the cable through the bolt), tighten the nut on the anchor bolt firmly, until you can see that it has actually flattened out the cable in the little hole. You should use both tools yourself to do the last hard tightening of the anchor bolt and nut (not too hard, though, or you will strip the threads). Un-release the brake (mountain bikers, hook up the short transverse cable; roadies, push the release lever up so it’s tight) and test the brake. If it’s a bit too tight or loose, adjust it with the sleeve at the hand lever end of the cable as described in the minor adjustment, above. Brake still way too loose? Do the major adjustment over.

(M) If your brake has a secondary anchor bolt in the carrier, you may need to adjust it a bit one way or the other so the mechanism is balanced, with both brake shoes the same distance from the walls of the rim, as shown in Figure 2-8. To adjust the secondary anchor bolt, loosen it, then slide the carrier up and down on the main brake cable until the brake pads are equidistant from the wheel rim. Then tighten the secondary anchor bolt.

(M, R) If a cable is broken, and you’re out on the trail or road, the best thing to do is make sure the other brake is adjusted well enough to work, then ride home with extreme caution and replace the broken cable with a new one.

(M, R) You can replace the cable if you brought along a spare cable with you on a ride, or if you are at home. First undo the anchor bolt on the broken cable and undo the secondary anchor bolt in the carrier if you have one, then pull the end of the cable out of the anchor bolt(s). Next, pull the cable out of the housing and ferrules, all the way back up to the handle. At the hand lever, loosen the lockring for the adjusting sleeve, if there is one, then twiddle with the lockring and the sleeve until the slots are lined up so you can swing the cable down and out. The barrel end will still be held in the lever itself; line up the cable with the re lease slot in the lever, then push the barrel sideways to get it out. On road bikes, you have to push and wiggle the ball end out of its socket in the lever.

(M ,R) Grease the new cable and thread it in carefully; slide the barrel end into the hole in the lever sideways, then slip the cable into the slots in the lever, the adjusting sleeve, and the lockring, keeping them all lined up as you go. Push the cable through the housing and ferrules, thread it through the secondary anchor bolt in the carrier if you have one, then through the anchor bolt. Tighten your new cable up as described in the major brake adjustment procedure earlier in this section.

(R) If you have an old-fashioned type of hand lever with no nifty slots to slide the cable out, removal is trickier. You may be able to jiggle the barrel end around until it pops out of its holder in the lever, or you may have to cut off the frayed and broken end of the cable, then push the whole thing backwards through the housing and the lever and out to freedom.

(M, R) If both cables are broken and you are miles from home, you have to figure out some way to use the rear cable on your front brake. First look at the broken end of the rear cable. Is the break near the mechanism end? If so, and if the break is a pretty clean one, all you have to do is take the cables out of their housings and put the rear one in the front brake system, using the replace the cable procedure, above. Make sure you get the little ball or barrel at the end of the cable set firmly in its notch in the hand lever, then thread the cable through the little ferrules and the housing on down to the front brake mechanism. If the cable end is too frayed to go through the housing, you have to find your way to a farmer or somebody who has a pair of good wire cutters to clip off the frayed end. When you have a good clean cut on the end of the cable, thread it in.

(M, R) Tighten your makeshift front brake, as in the major brake adjustment procedure earlier in this section. If you have extra cable left over, wind it up in a little coil and tie the coil with the end so it’ll stay out of the works as you ride cautiously home. Mountain bikers: Undo the rear brake’s transverse cable, too, so it won’t flop down and catch a knobby. Do a complete replacement of both your brake cables when you get home, as described above.

(M, R) Cable sticky. If you’ve ascertained, by the diagnostic method in the OVERALL BRAKE SYSTEM DIAGNOSIS section for the brakes, that your cable is sticking, it’s probably because the thing is either rusty, mud-clogged, or kinked.

(M) If the cable is rusty or mud-clogged, you can grab the carrier with one hand and the hand lever with the other and just horse the thing back and forth a whole bunch of times; with luck, you’ll loosen up enough of the crud inside the cable housing and ferrules so that the cable can do its job. If you have some lubricant, apply it at the places where the cable disappears into the housing and work it in as you horse the cable back and forth.

(M, R) If you are at home, or if you are out on the trail or road and have some time and lubricant, release the tension on the cable. Mountain bikers, pull the removable end of the transverse cable out of its slot in the cantilever. On a road bike, use the quick-release lever on the brake mechanism to loosen the brakes. Then pull the hand lever all the way to the bars; put oil or grease on the shiny (or rusty) sections of the cable that you have just pulled out of the housings. These normally unseen sections of the cable are usually the parts that cause the stickies. If they are really rusty, you need to replace the cable.

(M, R) If the cable housing has a kink (a sharp, unnatural bend in the springy, plastic-covered tube that the cable runs through), all you have to do is get a firm bare-handed grip on the housing on either side of that kink and straighten it. If the kink is at one end of the housing, like right next to the hand lever, make a mental note to loosen and remove the cable when you get home, then snip off the bent end of the housing, thread the cable back in, and reset the brakes. Don’t try this out in the backcountry unless you have a good pair of cable clippers along. You may not be able to get the brake back together if the end of the cable is frayed. If this is the case, just straighten the kink as well as you can with your bare hands and ride home to your cable-cutting tool.

(M, R) If you are at home and have a good cable-cutting tool, take the cable out of the kinked housing, then either cut the kinked end off the housing, or replace the whole length of housing. Either way, you’ll need to cut the housing; this takes a little know-how.

(M, R) To make a clean housing cut, one that doesn’t have a burr digging into the brake cable, either snip it crisply with your diamond-hole cable clipper (this works best if you have braided housing), or use diagonal clippers and slowly squeeze in on the cable housing. Wiggle and twist as you squeeze, so that the blades go in between the coils of the housing wire, instead of mashing a coil flat. When the clip per has worked its way slowly into a slot between the coils, squeeze harder and twist the clipper as you cut through. Twist the clippers sort of like you’re popping the cap off a soda bottle with a bottle opener, only sideways. Check the new end of the cable housing for burrs. (See Figure 2-7.) Is there one pointing out into the air? You can clip it off with the mashing type clippers, or file it down. If there’s a burr sticking into the hole in the middle of the housing, you have to make another cut. Remember to twist as you cut. It takes a little practice. But don’t use a housing with a burr that’s going to dig into your cable and gradually ruin it. Ever notice how you only break a shoelace when you’re in a hurry? The same logic works with brake cables. When a brake cable snaps, it’s usually when you really need it.

Info-graphic 2-7 Clean Cut and Burr in Housing End

Next: Brake Mechanism

Prev: Hand Lever