Knowing how to adjust rim brakes is essential for both performance and safety.
Though disc brakes may be the stopping power of choice for the majority of high-end bikes these days, most bikes out on the road are still likely to be fitted with rim brakes – so learning to adjust them is still invaluable for cyclists.
Note that in this guide, we’ll specifically be discussing how to adjust caliper rim brakes, which are most common on road bikes and often hybrids.
If you’re not sure which type of rim brakes your bike is fitted with, check out our Complete Guide to Bike Brake Types here – and keep an eye out for our upcoming guides on adjusting V-brakes and disc brakes too.
Advice on how to adjust rim brakes is one of the most common maintenance guide requests we get from our readers, so in this guide, we’ll be covering:
- What Are Rim Brakes?
- How Do Caliper Rim Brakes Work?
- Why Do Rim Brakes Come Out Of Adjustment?
- What Tools Will You Need To Adjust Rim Brakes?
- How To Adjust Rim Brakes in 6 Steps
- Robbie’s Video Maintenance Guide: How To Adjust Rim Brakes
Let’s dive in!
What Are Rim Brakes?
On modern bikes, there are two main braking systems used: rim brakes and disc brakes.
Disc brakes feature a brake rotor located at the center of the wheel, with small calipers that clamp onto it to generate friction and stop the bike. They used to be largely exclusive to mountain bikes, but are increasingly common on road bikes too.
Rim brakes come in several different forms, but always feature a braking surface around the wheel’s rim, which the brake pads clamp onto to create friction.
The most common types of rim brakes are caliper brakes, V-brakes, and cantilever brakes. We’ll be focusing on how to adjust caliper brakes (pictured below), as they’re the most common form.
You’ll find them mainly on road bikes and hybrids. They’re light, provide good stopping power, are easy to maintain and install, and are cheap relative to disc brakes.
How Do Caliper Rim Brakes Work?
Caliper brakes work on a very simple principle.
On the caliper, you have two brake pads, and they both sit on either side of the bike’s wheel next to the rim’s braking surface. Running through the caliper, you have a cable that goes to the brake lever.
When the lever is pulled, the tension pulls the cable tight, pinching the calipers together and pressing the pads against the rim. This friction slows the wheel down and brings the bike to a standstill.
Why Do Rim Brakes Need To Be Adjusted?
Before we get to the task at hand, it’s important to understand why rim brakes come out of adjustment. There are many reasons for it, and understanding why it might have come out of adjustment means you can stop it from happening again.
Caliper Wear And Tear
The first reason you are going to find your rim brakes coming out of adjustment is wear and tear.
Brake calipers are made up of many parts, such as springs, and over time these wear out, and even bolts can slowly work themselves loose.
Cable Stretch
The next issue many cyclists find their brakes coming out of adjustment is cable stretch.
Surprisingly, this happens on new bikes more than on old bikes. When installed, a cable takes time to bed in and lengthens, before evenly hitting a point where it doesn’t stretch anymore. At this point, it needs adjusting.
If your cables need replacing altogether, check out How To Replace A Bike Brake Cable In 5 Steps here.
Brake Pad Wear
Changing brake pads is a standard part of maintaining your bike.
Just because your pads might be slightly worn doesn’t mean they need chaining immediately. If they are not past the wear indicator, you can keep using them.
However, because the partially worn pads are effectively thinner than when they were installed, the rim brakes will need to be adjusted to compensate.
If you need new brake pads, check out our article on How To Replace Rim Brake Pads here!
Using Different wheels
If you change to a different set of wheels, your brakes must be adjusted. This could be to perfectly align with the rim or even to compensate for a thinner or wider rim.
Installing New Brakes
If you have decided to replace or upgrade your brakes, they are going to need adjusting and setting up.
What Tools Will You Need To Adjust Rim Brakes?
All you will need is an Allen key set, also known as hex keys. These are sold at most bike shops, or you will find them on your cycling multi-tool in your spares kit.
Having a bike stand is not essential, but will make this job easier and is much friendlier on your back.
How To Adjust Rim Brakes in 6 Steps
Step #1. Checks
First, we want to identify why the brakes are out of adjustment.
If it’s cable stretch or (partly) worn-down pads, then we can continue without the worry it will happen again.
If you find damage to the caliper, consider repairing it or completely replacing it.
You will also want to check the cable is in good condition and ensure there’s no uneven wear on the pads. If any worn parts need replacing, do it before you start.
Step #2. Release The Tension
Next, we need to release the tension from the brakes.
Go to the cable pinch bolt (pictured above) and undo it with the Allen key, and the calipers should release and spread open.
Now, locate the adjuster (the conical piece of plastic that screws onto the cable) on the caliper and wind it in completely, turning it clockwise. We do this so we can make better adjustments later in time, and if the cable stretches, we have plenty of room for movement.
Step #3. Apply The Correct Tension
Here we need to reapply the correct tension.
A quick way of doing this is to grip behind each pad with one hand and press the calipers inward until they’re 1 to 2 mm away from the braking surface.
While holding the pads here, grab the cable, pull it to create tension, and tighten up the pinch bolt again. It might take one or two attempts. If it feels a bit loose, don’t worry; we will use the adjuster next to tune it perfectly.
Now go to the lever and pull it. It will feel quite loose to start with. To tighten it, go to the barrel adjuster on the caliper or lever and tighten it up by unscrewing it while pulling it for perfect leverage.
Step #4. Check The Caliper Is Straight
Now, it’s time to check that the caliper is straight.
The pads should be an equal distance from each side of the rim. If not, use the Allen key to slightly loosen the caliper bolt on the back of the fork, straighten the caliper, and tighten it back up again.
Step #5. Adjust The Position Of The Brake Pads
To get our rim brakes working perfectly, we need to ensure the pads are in the right position.
The easiest way to do this is to slightly grip the brake lever until the pads touch just the rim brake’s surface.
Once they have gripped it, hold it there, take your Allen key set, and undo one of the pads by about half a turn. Although it will still be tight, you should be just able to move it.
Adjust the pad until it is entirely in line with the braking surface across its whole length, with no overlap on the tire or over the edge of the braking surface onto the rest of the rim.
Now, squeeze the brake lever a little more to hold it in place, and tighten it back up, before repeating the process on the other side.
Step #6. Test It
It’s now time to test the brakes to ensure they work properly.
We recommend doing this somewhere away from any risk. The brakes should feel sharp and firm and stop you quickly.
If they don’t feel responsive, we recommend going to that barrel adjuster and fine-tuning until you get it perfect. If you are still struggling, it’s worth checking with your local bike shop to see if there’s anything you’ve missed or whether any parts need replacing.
Robbie’s Video Maintenance Guide: How To Adjust Rim Brakes
Check out the BikeTips YouTube Channel here for walk-through bike maintenance guides and more!
A Final Note
Now you know how to adjust rim brakes!
Adjusting the rim brakes on your bike is a skill that will come in incredibly useful over your time as a cyclist. It’s not only going to make your cycling experience better but also, most importantly, safer.
If you’d like to know more about adjusting other types, check out our Ultimate Guide To Adjusting Bike Brakes: The 4 Key Types here!
