For those of us not riding bikes with a fixed gear, brakes are probably the most important component on our bikes to have properly adjusted. Whether you are a racer, daily commuter, or sunny day rider, we all have to be able to stop safely and, if the situation calls for it, quickly. Fortunately, adjusting brakes only requires a few wrenches and a little know-how.
The first step for any adjustment on a bike is to check the condition of your equipment. If your equipment is in poor condition properly adjusting your brakes can be difficult, if not impossible.
Are your cables or housing rusted, corroded, fraying, or broken? Replace them. Check the wear of your brake pads; if you can no longer see the wear markers it is time for new pads. If your brakes do not open and close properly, or if they are bent at all it may be time to replace them. If there is any doubt as to the condition of your equipment please stop by your local bike shop and ask an experienced mechanic to make sure your bike is safe to ride.
Start with the basic checks: Are your wheels in the dropouts? If the wheel does not look centered in the brakes, check to see if your wheels are fully in the dropouts. If you notice that your brake levers are hitting the bars when you pull them check if you have an open quick release. Once these checks are done we can now start with the adjustment of the brake system.
Adjusting the position of your brake pads
Brake pad position is very important for a properly adjusted brake – if the pad is too high it may make contact with the tire and cause a flat. If the pad is too low, you risk having the brake pad go into the spokes, which is bad. Both situations can cause uneven wear on the brake pad, which make perfect positioning of the brake pad difficult if not impossible. The ideal position for the brake pad is about 1mm down from the edge of the braking surface and parallel to the curvature of the rim.
To adjust, pull your brake caliper closed so the pads are touching the rim, and manually position the brake pad into the correct position. Once the pad is in the correct position, tighten the screw holding the pad to the brake arm. The pad will sometimes want to rotate with your tightening motion but this can be prevented by pulling harder on the brake lever so the pad stays in the same position, or by holding the pad in place as you turn the screw.
If the pad is perfectly parallel to the brake surface the pad may oscillate creating a very unpleasant squeaking noise when you brake. This this can be corrected by toeing-in, or angling the brake pad so that the leading edge makes contact with the rim first. To do this you can stick a small shim, such as a piece of rubber, under the back of the pad and repeating the steps above.
Centering your brakes
Centering your brake calipers allows for both brake pads to make contact with the rim at the same time. This is important in ensuring that both pads wear at the same rate, and that an equal amount of force is applied to the rim at the same time. A poorly centered brake caliper can force the rim to flex to one side under hard braking potentially upsetting your brake pad placement and affecting the handling of the bike.
If the brake is visibly not centered with one pad being closer to the rim than the other, loosening the brake-mount nut and using your hand to move the brake caliper into the proper position and retightening the brake should solve the problem.
For cantilever brakes this process is a little different, and the centering is done by adjusting the tension on the springs for each side with the tension adjustment screw. By turning the screw clockwise you increase the force of the spring pulling the arm away from the rim, so if the brake pad is too close on one side, loosen the adjusting screw by an 1/8th of a turn on that side and then tighten the screw by an 1/8th turn on the other side. Keep repeating this adjustment until the brake arms are centered.
Adjusting Cable Tension
Having the right amount of cable tension in the brake system is crucial for the brakes to generate enough stopping power to be safe. If you have too little tension, your brake even if they make contact with the rim will not be able to generate enough force to stop you, and too much tension on the cable makes it so you won’t have enough leverage when pulling your brake levers and you won’t be able to use the full power of your brakes. There are two simple ways to adjust cable tension. One utilizes the barrel-adjuster on the brake or next to your levers for minor adjustments. The other uses the cable clamp on the brake itself where you can make large adjustments.
To adjust your brakes first loosen the cable clamp bolt, letting all of the tension out of the system. Then reset the barrel-adjuster by screwing it all the way in and then out two full rotations, to allow you some fine adjustment capabilities later on. Next, with the quick release closed, hold the brake caliper so the pads are about 2mm away from the rim and pull the cable through, tightening it into position. The most important step is to check the brake levers. Are they too tight? Can the wheel spin freely when the brakes are not being squeezed? Are your brake levers hitting your bar? If yes to any of these questions repeat the steps above and hold the calipers closer or further from the rim as is necessary. Once you have the tension set to the right amount, double check that all the bolts are tight.
You should check your brakes frequently to make sure they are operating properly, and that you can generate enough force while braking to lock both wheels. Once learned adjusting your brakes is a quick and easy process that will benefit you throughout your cycling life.
by William Dawkins
William Dawkins has been in the bicycle industry for four years as a mechanic and a racer, and is a wonderful addition to the CycleU team.