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Nothing is more vital to your safety on a bike than the ability to stop!
Bike brakes come in various forms, whether they’re disc or rim brakes. At some point, they all get worn down or knocked out of shape, and then they need fixing.
This article tells you how to adjust bike brakes and what tools you’ll need for the job.
Types Of Bicycle Brakes
Before you attempt any kind of work on your brakes, of course you must identify the type of brakes you have.
Disc brakes work by squeezing a pair of brake pads against a centrally positioned rotor (disc) to create friction and stop the bike.
The benefits of disc brakes are many. They’re stronger than rim brakes, perform well in wet weather, don’t wear down your wheel and won’t cause tire blowouts.
Disc brakes come in two forms:
Mechanical Disc Brakes
Mechanical disc brakes use cables to transfer force from the brake lever to the piston, which in turn pushes the brake pads against the rotor.
Benefits of mechanical disc brakes over hydraulic include lower cost, easier maintenance, and wide availability of parts (same cables and levers as rim brakes).
Hydraulic Disc Brakes
Hydraulic disc brakes use hydraulic fluid in a sealed line to deliver pressure to a piston inside a master cylinder. This, again, pushes the brake pads onto the disc rotor.
Benefits of hydraulic disc brakes over mechanical include more efficiency, less frequent (but more difficult) maintenance, smoother and more responsive operation.
Read more: Do I need disc brakes for commuting?
Video: How Disc Brakes Work
Rim brakes are still common on new bikes, ranging from the cheapest models to high end dream machines.
All rim brakes use tensioned cables to transfer force from the brake lever to the braking track of a wheel rim. Two brake pads (aka shoes) are pulled onto the rim, forcing the wheel to a halt through friction.
Rim brakes come in three forms.
Caliper Rim Brakes
Caliper brakes are by far the most common rim brake on road bikes.
The most common caliper design is the dual-pivot side-pull caliper brake, with a cable that enters above the mechanism to one side. One caliper arm pivots at the center while another pivots at the opposite side to the cable.
Single-pivot caliper brake also have a cable pulling from one side, but both caliper arms pivot in the center of the mechanism.
Read more: Best road bike brake pads
Cantilever Rim Brakes
With cantilever brakes, two caliper arms are attached to separate pivots on either side of the wheel. A straddling brake cable is held above the wheel by a “carrier” and attaches to the calipers on either side. The pulled cable draws the brake pads together.
Video: Replacing A Cantilever Brake Cable
V-brakes are similar to cantilever brakes in that they have two discrete caliper arms pivoting on separate braze-ons, but the calipers are longer and more efficient. You’ll find V-brakes on almost all MTBs.
The V-brake’s cable housing attaches to one brake arm via a “noodle”, and the inner cable continues on to an anchor bolt on the opposite side. When the cable is pulled, the two arms are drawn together, moving the brake pads towards the brake track.
Tools Needed To Adjust Or Tighten Your Bike Brakes
The tools you’ll need to adjust brakes will vary depending on what type of brakes you have, but many will be useful regardless. Here’s a list:
- Allen keys – hex keys (or Allen keys) are universally useful. Common sizes needed for brake adjustments include 3mm, 4mm, and 5mm. You’ll find all these sizes in the Pedro’s L Hex Wrench Set.
- Philips screwdriver – often be useful for making adjustments to brake assemblies. A multitool like the KER 11-in-1 gives you several different bit sizes.
- Torx wrenches – Torx screws are common among brake mechanisms and elsewhere on bikes. The Park Tool TWS-3 Torx Y Wrench incorporates three useful sizes in a three-way design.
- Torque wrench – a torque wrench set is usually optional for brake adjustments but useful elsewhere if you have a carbon bike.
- Rotor truing fork – a rotor truing fork or adjustable spanner is handy for gently straightening bent disc rotors.
- Cable puller – also known as a “fourth hand tool”, a cable puller is useful for one-handed cable tensioning.
- Hydraulic Piston Press – a hydraulic piston press is useful for replacing or aligning pads and other maintenance tasks.
- Cable cutter – a cable cutter is always useful for cleanly cutting brake and gear cables upon installation or repair.
- Brake bleed kit – bleeding hydraulic disc brakes using a brake bleed kit will remove any air bubbles from brake lines, thus maintaining efficiency.
How To Adjust Caliper Brakes (Rim)
There are a few steps to go through when adjusting caliper brakes.
1. Centering The Brakes
The first thing you’ll want to do with caliper brakes is center them so the brake pads are equidistant on either side of the brake track. This is done via a bolt that passes through the crown of the fork, usually using a hex key.
It’s important that the brakes are centered so that the pads or shoes engage with the rim at the same time. You might occasionally have to do this if you’ve accidentally knocked the brake assembly or it’s just worked its way loose.
2. Altering Pad Distance
The distance of the brake pads/shoes from the brake track is a personal choice. The closer they are, the firmer braking becomes. Some cyclists prefer some travel in brake levers before the brake pads engage.
To adjust pad distance, you have to hold the calipers at the required distance with one hand and loosen the bolt holding the brake cable. At that point, you may increase or decrease the cable’s tension and change the distance of the brake pads.
The above task can be fiddly and is where some people turn to a cable puller.
3. Align Brake Pads
The brake pads should contact the brake track in the middle. This means not dipping below the braking surface nor catching the sidewall of your tire. A brake pad rubbing on a tire will damage it and may eventually lead to a dangerous blowout.
One easy way to align brake pads is to position them against the rim when still loose and while squeezing the brake lever. This stops them moving. Once you’re happy with their position, you can tighten them up and release the brake lever.
4. Using The Barrel Adjuster
For minor adjustments to the brake pad distance, you can use the barrel adjuster. Clockwise turns move the pads away from the rim and counter-clockwise move them towards it.
How To Adjust Disc Brakes
There are many facets to disc-brake maintenance, so here we’ll describe how to align your disc brakes and eliminate brake rub.
1. Wheel Alignment (older bikes)
A common cause of brake rub in older disc-brake bikes is a poorly installed wheel. Most modern disc-brake bikes have a thru axle, making it impossible to install badly, but a quick-release wheel can sit unevenly in dropouts.
If you own such a bike with QR skewers and dropouts, ensure the wheel is installed properly before proceeding to other steps.
Video: Wheel Installation With Quick Release Skewers
2. Reset The Brake Caliper
If the caliper isn’t centralized, brake rub can result. To fix this, loosen both of the brake caliper bolts that attach the caliper to the frame or fork. Firmly apply the corresponding brake lever and then retighten the bolts before releasing the brake.
Repeat the above process if necessary for best results.
3. Reset The Pistons
If the first process does not solve brake rub, try resetting the pistons. Remove the retainer pin and disc brake pads to begin the process. This may involve removing the wheel to allow access.
With the pads removed, use a hydraulic piston press or non-metal tire lever to push the pistons back into their recess as far as you can. Replace the pads and the pin as well as the wheel if necessary (you might be able to do this with the wheel in place).
4. Fixing A Bent Disc Rotor
A disc-brake rotor has to be true enough to pass through your brake pads and calipers to function properly. A warped rotor may drag against the brake pads, even if it reluctantly passes through the calipers.
You can true a disc rotor simply by bending it into shape with a rotor tuning fork, or a small, clean adjustable spanner.
Video: How to True Disc Brake Rotors
How To Adjust V Brakes (Rim)
V-Brakes are commonly used on bikes that need clearance for fatter tires and mud. But how are they adjusted?
1. Adjust Tension (If Necessary)
If the brakes are not coming into contact with the rim, you must tighten the cable. To do this, start by winding the barrel adjuster on the brake lever almost completely in and then loosen the anchor bolt on the brake mechanism.
Squeeze the brake arms and pull the cable through before retightening the anchor bolt when the brake pads are close to the rim (not touching). The brakes should now work.
2. Align Or Realign Brake Pads
As with caliper brakes, a great trick for aligning pads is to loosen them just enough that they can be moved, squeeze them onto the rim with the brake lever, move them into the required position and tighten them up again while in position. Let the brake lever go.
Once you’ve done this on both sides, pull the brake lever and make sure the brake pads meet the rim symmetrically.
3. Adjust Return Springs
To ensure the right and left pads make contact with the rim at the same time, you can adjust tension in the return springs at the base of each caliper. These will require either a Phillips screwdriver or a hex key.
Increasing tension in the springs with a clockwise turn moves the pad away from the rim. Decreasing tension counter-clockwise keeps the pad closer to the rim. Attempt to balance tension in the springs and keep them in the middle of their range.
4. Turn Barrel Adjusters
Barrel adjusters adjust the levers of V-brakes and the amount of travel required to operate them. Adjust these to suit your personal taste!
Read more: How to fix noisy brakes