Description Of The Problem
When the rider releases the brake lever after applying the brakes, the brake arms/jaws do not open fully, and the brake shoes continue to rub against the rim or the rotor.
Possible Sources Of The Problem
- Broken Return Springs
Brakes have a spring that re-opens the brake arms once the lever is released. The spring type depends on the model of the brakes.
In the image above, you see a set of caliper brakes found primarily on road bikes. The jaws are re-opened by the thick steel wire at the back of the brake.
In different, V-brakes have a separate spring for each brake arm.
It’s also worth mentioning that V-brakes have a bolt through which one can adjust the tension of the spring. Playing with the setting could help in this scenario.
Sometimes the return spring of rim brakes pops out. The fix is fairly easy. You just have to press the spring back in position as shown in the video below.
Meanwhile, disc brakes have a return coil spring inside the caliper. If the coil spring malfunctions, it can be replaced.
- Improperly Routed or Contaminated Cable and/or Housing
If the brake cable and housing are not routed correctly, the return spring could fail to pull back the cable sufficiently. This problem won’t necessarily show when the rider is squeezing the brake because his grip is much stronger than the return spring. However, when the return spring has to do all the work, the routing could interfere.
Examine the cable routing for weird twists. If the bike is new, this is unlikely to be the problem, but if an inexperienced mechanic has worked on the bike, they may have made a mistake.
Contamination and tears along the housing can also contribute to the issue. If the housing and the cable are old, it’s recommended to replace them.
To diagnose the cable and housing, you can disconnect the brake cable from the brake and try to close the brake arms by hand. If the brake arms pop back to their original position with ease, chances are that the cable and its housing are the culprit.
- Rusted Brake Studs
The brake bosses/studs to which V-brakes and cantilever brakes are mounted are made of steel and can sometimes rust. When that happens, the brake pivots will be prevented from rotating freely. The solution is to remove the brake and clean the studs.
- Contaminated Pivots
If the bike is old and/or fairly neglected, there could be a lot of dirt between the brake pivots and the mounts. In that case, it will be helpful to remove the brake and clean the area with a degreaser. Be careful not to contaminate the brake shoes.
- Bent Rim Or Rotor
If the rubbing is only on one side, the problem could be a bent rotor (disc brakes) or rim (rim brakes).
In that scenario, the brakes may actually be opening sufficiently but due to the deformation of the rim or rotor, the brake pads on one side may continue to rub.
If that’s the problem, it will be necessary to true the rim or straighten the rotor. Those procedures are not incredibly complicated but could be intimidating for a beginner (especially the rim truing).
- Jammed Brake Lever
In rare cases, the problem would come from the lever. If the cable hasn’t been properly routed through the brake lever or if there’s a small object in the lever, the lever could fail to return to its starting position and thus keep the brakes closed.
If this is the problem, it will be evident because the lever won’t move much after activation.
- Brake Pads Too Close To The Rim/Rotor
If the brake pads are extremely close to the rim or rotor, they will rub even when the brakes are returning to their original position.
Most of the time, this problem comes from a brake cable that’s tensioned to the point where only a minuscule movement of the brake lever initiates full contact between the pads and the rim/rotor.
This is a bad setting because it gives the rider poor brake modulation (control over the braking force). It will be necessary to reduce the cable tension to a less tense setting.
What Will Happen If I Don’t Fix This Issue?
The brake system of any vehicle is crucial for both performance and safety. Bicycles aren’t an exception. If the brakes are not releasing, the rider will face the following side effects:
- Jammed wheel
If the problem is severe, it’s possible for the brakes to fully bind against the wheel and lock it. The outcome could include a sudden fall for the rider.
- Pre-mature wear of the pads
Since the pads will rub even when the brake is not activated, the rim/rotor will quickly eat through them.
- Loss of Energy
Riding a bicycle is hard enough with “free wheels”. When you’re fighting your own brakes, pedaling becomes extremely non-efficient.
- Unpleasant Rides
Riding with wheels that can’t rotate freely is simply not fun.
For safety, performance and pleasure purposes, it’s recommended to fix this problem immediately.