How To Adjust Rim, Cantilever & Disc Bike Brakes Yourself
Got brake rub? We’re all bound to deal with squeaky, tight, or maladjusted brakes at some point during our time on the bike. But the good news is that most of the fixes are ones that you can do at home or even on the fly.
Mike Perejmybida of VeloFix has been a mechanic for over 10 years, and he’s seen hundreds of do-it-yourself disasters from brake bleeds gone wrong to adjustments that resulted in bigger problems. Here, he explains a few tips and tricks for adjusting your disc brakes, rim brakes, and even cantilever brakes – and when you should seek professional help so you can avoid a disaster of your own.
Disc brakes – on a road bike, mountain bike, or cyclocross bike – might seem intimidating, but Perejmybida says they’re actually the easiest to adjust.
If you think you have brake rub, start by loosening the two bolts that mount the disc brake to the frame. Once they’re loose, Perejmybida says to squeeze your brakes so that they engage the rotor. It’s now centered perfectly, so – with the brake levers still depressed – re-tighten those bolts. That fixes about 75 percent of disc adjustment problems, Perejmybida says.
Rotor still slightly rubbing, but you can’t feel it? Don’t freak. “Almost no rotor is perfectly straight,” he says. If it’s an annoying rub that affects your ride, you can use a rotor straightening tool like Park Tool Rotor Truing Fork. Set the bike in a stand or flip it so the wheel can spin freely. Look for a wobble, or a gap opening and closing, between the pads to identify if the rotor is out of true. Note the section that needs truing and rotate it away from the caliper.
Gently work the tool around the rotor at that section to straighten it if slightly warped. This only works if the rotor is rubbing in one specific spot. If you’re unsure if it’s the rotor or the brake, you’re probably better off taking it to a professional to get it done right. “If you do try it yourself, remember that they’re really fragile so be very gentle,” he says.
To check your brake pads, look in the top or back of the brake to see the side profile of your pad. If the spring that keeps the pads together looks perilously close to the rotor, if you can’t see the pad at all, or if your pistons are stuck out as far as they can go, it’s time to replace them, Perejmybida says.
Replacing them is quite simple. “There’s a pin that you undo, the brake can stay on the bike, and the pads come out from the top of the brake,” he explains. After you put the new pads in, press the pistons back gently with the flat side of a big, wide flathead screwdriver to make room for the new, thick pads so they don’t start rubbing immediately.
Pro Tip: “Always, always make sure that the wheel is in the frame properly,” Perejmybida says. “So often, people don’t have the wheel seated in the frame right, and they end up adjusting the brakes entirely wrong.” This isn’t a problem with through axles, but most road bikes with disc brakes still use quick release skewers. Perejmybida suggests flipping the bike upside down or putting it on a stand to make sure the wheel is seated correctly, not at an angle.
When to Seek Pro Help: bleeding brakes. If your brakes suddenly feel super tight, are increasingly mushy, or one of your pistons in the brake is stuck, your hydraulic brakes may need a good bleed. In this case, it’s worth getting the help of a pro. The fluid can be a mess, Perejmybida says. And getting the fluid in without air bubbles is tricky. Do yourself a favour and don’t try this at home. Treat it like your car’s oil change and get it done around every 5,000 kilometres, even if you don’t feel any issues.
Start by using what’s in place for you already: the barrel adjuster that’s at the top of the brake lever on the cable. Just playing with tightening or loosening this can solve a lot of common issues, Perejmybida says.
If that doesn’t work, you can check the bolt where the brake is connected to the frame. When the bolt isn’t tight enough, it can cause your entire brake to move as you ride. Similar to disc brakes, Perejmybida says to engage your brakes, and then tighten that bolt so it’s centered.
If your brakes are too loose – meaning you need to pull the levers way too hard to the bars to get the brakes to engage – Perejmybida suggests slightly tightening the cable. It’s a simple adjustment: Using an Allen key, loosen the nut and bolt where the cable ends, pull a bit more of the cable through, and retighten. (Try the barrel adjuster before you try this, though.)
When trying to adjust the brake pads to hit the same spot on the rim on either side, Perejmybida suggests tightening the brakes with the barrel adjuster first. Once the pads are tight to the rim, you can loosen the bolt that keeps them in place and make minor adjustments without them slipping too far to one side, since the rim itself will keep them in place. “It’s like having a third hand,” Perejmybida says. Loosen the barrel adjuster after they’re in place.
Pro Tip: If you’re at the start line of a race or group ride and realise your brakes are rubbing, you can use the switch on the side of most rim brakes that’s used to slightly loosen the brakes in order to remove the wheel. (Make sure you can still stop the wheel easily.) After the ride, tighten it back up and properly adjust them, don’t just rely on that switch.
When to Seek Pro Help: truing your wheel. If your wheel is still rubbing in one specific spot after adjusting your rim brakes, that might mean your wheel is the issue – not your brakes. Bring the bike to a local mechanic.“Just don’t try to do this yourself,” Perejmybida says. “That’s not a bike part you want to mess with.”
If you’re old-school, you might still sport cantilever brakes, in which the two brake pads are controlled by wires that pull up as you apply pressure to the levers. They may look like the simplest of the bunch, but they are actually the hardest to adjust on your own, Perejmybida says. That’s because in order to avoid brake chatter and jamming one brake pad into your rim while the other floats on the opposite side, they need to be set up perfectly.
It’s all about symmetry, Perejmybida says. That means making sure that the wires controlling the left and right brake pad are exactly the same length, and that the brake pads are sitting in exactly the same place on the rim. That doesn’t require much by way of tools—you can make these adjustments with an Allen key – but it does require a lot of patience as you make minor adjustments and keep testing to find the perfect balance.
Pro Tip: Keep an eye on these brake cables, as they’re exposed to the elements and are likely to fray over time. If your braking feels sloppy, or it’s getting harder to pull the levers, it might be time to replace the cable, not just adjust the brakes.
When to Seek Pro Help: Initial setup. Rather than trying to get your brakes perfectly symmetrical the first time you’re putting your bike together, get a mechanic to handle that headache. Afterwards, Perejmybida says, it gets easier. But if you have them set up wrong to start, it’s going to be nearly impossible to get them perfectly tuned.