If your road bike's caliper brakes just aren't up to scratch, not even the best bike helmet in the biz will save your poor noggin. Here are six issues you should regularly check for, and how to address them.
Possible problems: Let's start with the most obvious consumable component: the brake pads. Are they properly aligned with the rim's braking surface? Are they completely worn out, or worn out unevenly (see left)? Brake pads can be replaced at little cost, but if you're feeling thrifty you can squeeze plenty more miles out of them with some simple maintenance.
How to fix this: Flatten and refresh the brake pad surface by using a file or a bench grinder to reveal fresh rubber that will better grip the braking surface. Pick out any road debris or tiny metal shards that may have become embedded in the brake pad surface (see left). These act as a scouring pad on your rims when you're braking, wearing them out prematurely. You can do this with a nail, or – my preferred "tool" – the business end of a sharpened spoke.
And clean the rim braking surface itself while you're at it. Oil and grime and road dirt will stick to them, compounding the scouring effect I mentioned above. If you ride in the rain, or in winter, make this one of the main parts of your bi-weekly – or whatever – bike maintenance regime. No need to use any powerful solvents, though: a clean rag and some elbow grease will suffice. Just keep wiping them rims until your rag comes out almost clean.
Lastly: if your bike has steel rims, consider upgrading at least one of the wheels to aluminium-rimmed ones for better stopping power—especially in the rain. There is more friction between rubber and aluminium than steel, and friction is what we want when it comes to brakes.
Possible problems: If your brakes suck because the brake lever needs to travel relatively far before the brakes engage, you'll need to tighten the brake cable. A related issue might be that the cable no longer freely slides through its housing, either due to water and dirt contamination, or due to the cable being frayed or torn.
How to fix this: A loose brake cable can be tightened on one of two ways, as labelled on the image to the left. Minor adjustments can be performed using the "barrel adjuster" (1), a fancy term for a long bolt that threads into the caliper arm that can be backed up a few turns to tighten the cable. The rusty nut you see in the image to the left locks the adjustment in place; gently loosen it with an 8mm wrench or a pair of needle-nose pliers and unthread the bolt a few turns. This will tighten the brake cable, which brings each of the brake arms closer to the braking surface. Now spin the wheel and make sure neither pad rubs against the rim over the course of one turn of the wheel. If there is rubbing, loosening the barrel adjuster a bit can compensate for you having overly tightened the brake cable.
To inspect the brake cable, loosen the pinch bolt (2) that fastens the brake cable to the caliper, and pull the cable out. A brake cable is just a bunch of braided strands of steel wire; check if one of the strands has been torn and begun to fray (see left). Check for rust and contamination on the cable and replace both brake cable and housing if the former doesn't slide smoothly through the latter.
(Aside: There's a whole debate online, and IRL, about whether you should oil, or even grease, your brake cables. One camp – the greasers – maintain that some light lubrication of brake cables is just what the bike doctor ordered. Those who prefer to keep things clean, however, point out that the inside of modern cable housing is teflon-coated, and that any lubricant you add will dry out and attract dust, prematurely contaminating it.
My own thoughts on this are that if you're reusing cables and housing that may be a bit rusty and sticky – which you shouldn't, because new ones are cheap and replacing them is easy – adding a lubricant will make them slide through each other better, at least in the short term. Otherwise, keep new cables as clean as possible when installing them.)
Possible problem: It's possible that, when at rest, the two brake caliper arms to which the brake pads attach are not at an equal distance from the rim; or that when you squeeze the lever, one pad makes contact with the rim before the other does.
How to fix this: In that case, you should realign the brake caliper. Loosen the nut on the back of the brake bolt with a 10mm wrench, realign the caliper and retighten the nut. You don't need to use all your might to tighten this nut, though, as it can turn the entire brake bolt in the process, totally messing up the caliper's alignment. Now spin the wheel, and squeeze and release the brake lever to assess the effect of your realignment; watch closely where the brake arms sit with respect to the rim when you release the lever. It may take a few tries to get this alignment right.
Possible problem: Consider the brake lever. Does it spring back when released? Is it all wobbly and bent? Has it been damaged in a crash?
How to fix this: If the brake lever doesn't work properly, replace it. It is also worthy to note that newer levers all feature a barrel adjuster that allows you to tighten the brake cable without undoing the pinch bolt on the brake caliper, as explained in section 2 above.
Possible problem: If everything we've looked at so far checks out, but the brake caliper doesn't unclench when you release the brake lever, it could be that its spring has become rusty and seized. The caliper spring in the top image, which has endured two winters, is starting to behave in this manner; but it's still springy enough to be functional.
How to fix this: One short-term solution is to clean around the brake arms and apply some oil. The best fix, however, may be to replace the entire brake mechanism. Consider upgrading to a modern "double-pivot" caliper, shown in section 2 above, for increased braking power.
Possible problem: This one can be a bit more subtle. A caliper brake is basically just one long bolt that passes through the fork, with things attached to it. Behind the forks, a nut fastens the entire mechanism in place. In in front of the fork, the caliper arms are held in place by a pair of nuts that are tightened against each other. If these nuts loosen, play can develop in the caliper arms. Check for this by squeezing the brake lever and pushing forward on the handlebars; if both brake arms move forward more than half an inch, say, before the braking engages, this may well be the case. Confirm the extent of the problem by grabbing each brake pad and attempting to wiggle them in opposite directions; also check if you can turn the acorn nut using only your fingers. (Caveat: it could also be your bike's headset that is loose, causing the front fork itself – and not the caliper arms – to wobble slightly back and forth. Here's how you deal with a loose headset.)
How to fix this: This adjustment can be a bit tricky. You'll need a pair of wrenches: one to advance the inner nut until play in the caliper arms has almost disappeared, the other to tighten the acorn nut against it to hold the former in place. If play in the caliper arms has disappeared but the arms no longer retract fully or evenly when your release the lever, you have made this adjustment too tight. Back up on the acorn nut slightly, hold it in place, and then turn the inner nut counter-clockwise against it to lock the two in place. Re-assess. (The principle behind this process is the same as adjusting a bike hub.)
Respect – and regularly inspect – your brakes, dammit! You don't want to sail into an intersection and flop onto a car's windshield because your brakes are too weak. (Like this guy.)
[Images by author]