Most bicycle brakes are activated by a set of cables attached to the brake levers, and most problems with your brakes can be solved by adjusting the tension of those cables. They will also need periodic adjustments to keep them functioning properly.
To check the tension of the brake cable, squeeze the brake lever. If they touch the handlebars or come close enough to crush a finger underneath, you need to increase the tension of the cable. On the other hand, if the slightest pressure on the brake lever causes your brakes to clamp — or if the brake pads rub as you spin the bike wheel without squeezing the brake lever — then you need to reduce the tension on the cable. Usually, the tension of the cable can be changed by turning the barrel adjuster found at the point where the cable meets the arm. There are many easy ways to do it videos on YouTube show you how brake cable adjustment.
There are several types of brakes, but you will most likely have rim or disc brakes. The most common rim brake — V-brake or caliper brake — clamps both sides of the wheel rim from the top of the wheel. Disc brakes don’t touch the rim at all and instead use small brake calipers to clamp CD-sized discs mounted in the center of each wheel. Disc brakes offer outstanding stopping performance, but they can be difficult to maintain.
The nicer disc brake uses a hydraulic mechanism to clamp the disc. While hydraulic brakes aren’t impossible to maintain at home, they’re a bit too much for most people to deal with. Be sure to periodically check the wires and fill them with fresh fluid at a local bike shop. And if the brake fluid reservoir on your handlebars seems to be running low, take it to the bike shop soon.
Less common is the wheel brake, which uses no lever and is instead actuated by reverse pedaling. These are difficult to self-adjust and dangerous when not adjusted properly, so take your brakes to a professional.
Brake pads wear out as you use the bike and are easy to replace. You just need to know the size or type of brake pad to buy. Writing on worn pads will give you hints on what to buy. Brake pads are largely universal, although their mounting systems vary. The beginning of This video explain the difference.
Replacing worn V brake pads with new ones takes no more than a few minutes, and all you usually need is a properly sized hex key. We suggest Park Tool’s hex wrench ($14) with the three most popular key sizes on it. It will take a little longer for you to change disc brake pads because brake pads are smaller and more complex; This video shows several ways to approach gasket replacement. In either case, it is recommended that you re-adjust the cable tension after inserting the new spacer.
You will also need to clean those brake pads periodically. Use an old toothbrush or towel shop ($3) to get into the gap between the brake and the rim or disc, and use some Brake cleaner ($10) to remove any buildup.
