Bike brakes are meant to do one thing, and one thing only: stop your bike in its tracks.
But sometimes they work a little too well, and refuse to stop…well, stopping.
So what causes brakes to get stuck, and what can you do about it?
Stuck bike brakes can be caused by damage, dirt buildup, or incorrect setup (among other things). Luckily, there are simple solutions to these issues that you can try at home! Or, if you don’t feel comfortable troubleshooting and fixing bike brakes yourself, then it’s best to talk to a bike mechanic instead.
In this article, I’m going to dig into six common issues that can cause your bike brakes to get stuck, and we’ll also walk-through potential fixes. Let’s jump in!
Table of Contents
Six Common Causes of Stuck Bike Brakes
While the solutions to fixing stuck brakes depends on whether your bike has disc or rim brakes, the causes of those problems are very similar. Here I’ll address the most common causes.
I’ve listed the below issues in order of the degree of “tech savviness” required to fix them.
What do I mean by this??
The first causes will require less “brake work” to fix, while the latter may require complete disassembly.
1. Bent Rim or Brake Rotor
Let’s start with rim brakes. If your brakes are sticking or engaging unevenly, it may not be an issue with the brakes at all. It could be that the bike rim is bent out of shape.
Check this by spinning the wheel and visually inspecting to see if the rim is spinning straight or wobbling back and forth.
If you have disc brakes, you’ll want to look for a bent brake rotor. Same as with rim brakes, spin the wheel and watch to see if the rotor is warped.
It will also be easy to hear: if the rotor makes contact with the brakes during its rotation, you’ll hear that lovely metal-on-metal grinding sound.
A bent rotor could cause inconsistent brake piston engagement. The pistons push in on either side of the rotor when the brake levers are pulled, causing you to slow down. By pushing half of the pistons in too far, the other half will be forced to compensate and come out farther than they should.
2. Too Much Cable Tension
Mechanical bike brakes are actuated with cables. When you pull the brake lever, the cable moves the brake pads in toward the rim or rotor, and you slow down.
If the cable tension is too high, it could force the brake pads to clamp down too hard, and then get stuck in that position.
To check your cable tension, pull on your brake levers. If you feel heavy resistance early in the levers’ travel, your cable tension could be too high.
Nobody wants to just lightly touch the brake levers and then go flying over the handlebars!
3. Brake Caliper Not Aligned Properly
The brake caliper houses your brake pads and pistons. When centered over your brake rotor or rim, the brake pads make contact at the same time when the brake lever is pulled. If it’s off-center, one brake pad may make more contact than the other, causing uneven pad wear.
If it’s really off-center, one brake pad may actually rub against the brake rotor or rim the whole time you’re riding. This will prevent your wheel from spinning freely and create excess drag.
4. You Squeezed the Brake Lever With Your Wheel Removed!
Oh, how many times this has happened to me…
To learn how my brakes worked, I would take off my wheels, squeeze the brake levers and watch how the pistons moved the brake pads.
However, when attempting to put the wheels back on, I noticed there seemed to be less space in between the brake pads than when I removed the wheels a minute before. So little space in fact, that the brake rotor wouldn’t fit in between the pads.
I soon found out that without a brake rotor in between to push against, the pistons will wiggle themselves right out of the caliper if you keep squeezing the brake levers, taking the brake pads with them.
If you have mechanical brakes, having the pistons pop out is annoying, but isn’t a huge deal. But with hydraulic brakes, hydraulic fluid can leak out if the pistons move out too far. Fixing this will require bleeding your brakes and replacing the fluid. This is something I’m not equipped to do myself, so it would mean a trip to the bike shop before riding again.
5. Dirt Buildup In Between Pistons and Brake Pads
Dirt has a habit of getting everywhere and ruining everything.
If gunk builds up in your brakes, it can inhibit the pistons from releasing, which will cause the brake pads to get stuck against your brake rotor or rim.
6. Brake Pads are Worn Out
As you use your brakes, the brake pads will wear out. The more they wear, the thinner they will get. The thinner they get, the farther the pistons will need to push them to contact your brake rotor or rim. Eventually, there won’t be enough material left to help you stop safely.
At this point, your brake pads–or what’s left of them–will be pushed together so close that they could contact your rotor or rim even when you’re not squeezing the brake levers.
How to Fix Stuck Rim Brakes
1. True Your Wheels
If you discover your rim is slightly warped, it’s possible to whip it back into shape by truing your wheel: a fancy word for adjusting the tightness of your spokes until your wheel is straight again. Though time consuming, it’s a pretty straightforward process.
Check out this video if you want try and tackle the job yourself:
If your wheel is really bent, this could be a sign of significant damage: make sure to check for cracks or sharp edges. If you find this type of damage, don’t waste time truing your wheel: it’s time for a replacement!
2. Adjust Cable Tension
Adjusting cable tension can be a little tricky, so I would highly recommend watching this video a few times before attempting it to make sure you do it right!
Again, if you’re not confident that you can do this yourself, it may be best to get the help of an expert at a local bike shop.
3. Realign Caliper
To correct the issue of misaligned calipers, we actually have to fiddle with the brakes a bit. But it’s actually pretty easy!
The same video above covers this topic too (beginning at 2:16), so follow along to make sure both brake pads are engaging at the same time.
4. Readjust Brake Blocks and Toe-In Pads
Moving the position of rim brake blocks is a pretty simple process. And if you’re doing this already, then you may want to “toe-in” the brake pads (so the front of the pad contacts the braking surface before the back end) to increase stopping power!
Once again, refer to the video above (beginning at 2:54) for a step-by-step guide. This one video sure does pack a lot of value into five minutes!
5. Clean Your Brakes!
Cleaning your bike tends to fix a lot of problems.
Use a degreaser and get all the gunk out from any crevices or exposed cable sections and wipe off the brake pads and rim braking surface with a clean cloth.
Make sure not to use bike lubricant on any brake components! Lubricant reduces friction, but friction is what brakes rely on to stop. This can be dangerous and can make it slower and more difficult to stop your bike.
6. Replace Brake Pads
If your pads are worn out, they’ll have to be replaced. If you just loosened them to adjust and toe them in, check the brake pad surface. If they’re worn down, buy a new pair and throw them on before doing any further adjustments.
How to Fix Stuck Disc Brakes
1. Realign Brake Rotor
Similar to a bent rim, a bent rotor can cause uneven braking. Fortunately, it’s a lot easier to fix than truing a wheel…and a lot less time consuming!
You can bend your rotor back into alignment using a designated tool (or any similar sturdy metal or plastic tool) as shown in this video:
If your rotor is significantly bent or shows any type of damage, you should replace it for better braking performance and safety.
2. Adjust Cable Tension with Barrel Adjuster
The barrel adjuster is the rotating plastic piece that sits at the end of your brake cable where it feeds into your brake lever. If too much cable tension is causing your brakes to lock up on your rotor, you can use this to loosen the tension.
Pay close attention to these steps, because they can be counterintuitive!
Rotate the barrel adjuster clockwise or counterclockwise from the perspective of the brake cable looking at the brake lever. Rotating the adjuster clockwise will release tension on the cable, while rotating counterclockwise will increase tension.
So if you want to reduce cable tension, rotate the barrel adjuster clockwise about ½ turn at a time, and squeeze the brake levers to see if you feel a difference in where the brakes engage. Repeat this process until the tension is at your desired level.
But what if your brakes don’t have barrel adjusters?
Well then you have hydraulic brakes! You would need to bleed your brakes to adjust the tension, which if you’ve never done before can be a frustrating experience. It’s probably best left to a bike mechanic to avoid excess brake oil–and expletives–flying everywhere.
3. Realign Caliper
The solution to a misaligned disc brake caliper is the same as with rim brakes; but the process is a little different.
Check out the same video from disc brake solution 1 above (beginning at 2:26) for a step-by-step guide to realigning your brake caliper for more even braking!
4. Push Pistons Back Into Brake Caliper
Now we’re getting a little more involved. If you’ve taken your wheel off and can’t get it back on because the brake pads have slammed shut, we’re going to need to remove the brake pads and push the pistons back into the caliper.
It may sound intimidating if you’ve never taken your brakes apart, but it’s relatively simple!
Check out this video from Seth’s Berm Peak channel for an easy guide to getting space back between those pads:
And next time you take your wheel off…use a spacer between the pads! I had to learn this the hard way too.
5. Clean Your Brakes
Disc brakes need some love too!
Refer to the cleaning guidelines in the rim brake section above.
6. Replace Brake Pads
It doesn’t matter what kind of brakes you have: if the pads are worn, your braking performance will suffer.
If you removed the brake pads for solution 4 above, then take a look to see if they need to be replaced. If they have deep grooves worn in them from the rotor, or there isn’t much material left in general, get yourself a fresh pair!
What to Do if a Repair is Beyond Your Abilities
Many of these solutions are easy fixes, and don’t require much technical knowledge to tackle. After all, I’ve tried all these on my brakes, and my mechanical abilities are near non-existent!
If you don’t feel comfortable trying any of these solutions, talk to a bike shop mechanic. Since brakes are a pretty important safety component, it’s better to seek professional help and get things fixed correctly than to risk making a mistake.
A good bike mechanic can even show you how to fix things on your own in the future if you’re willing to learn. You never know when you might need to apply those skills on your own bike or someone else’s. Fix someone’s bike when they’re in a bind and you’ll have a riding buddy for life!