Disc Brake Adjustment
Welcome to the Workshop Series. Today we’ll be guiding you through the disc brake adjustments.
The basic tools you may need for this job are: a 4mm and a 5mm hex keys and a torque wrench.
The reason for this adjustment would be if you’re experiencing poor braking performance or rotor rub.
Before starting any adjustments on your disc brake there are a few key things to note:
The brake rotors as well as the brake pads are wearable components and have a lifespan. It’s crucial to have adequate life left on those in order to achieve good braking performance.
Contaminated or glazed brake pads will affect your braking performance and are prone to cause a squealing noise. You can try sanding the pads down and cleaning your pads and rotors with an alcohol solution. However the best thing to do here would be to thoroughly clean the rotors and replace the pads.
If you are experiencing a squishy feel when engaging your hydraulic disc brakes, you’re more likely to need a brake bleed, which will not be covered on this video. If that’s your case, we recommend taking your bike to your local bike shop and let the professionals do their thing.
Sometimes you can have brake rub even with perfectly adjusted brakes, and that’s due to the wheel being installed incorrectly and out of alignment. This would affect rotor position and potentially cause rotor rub. So before starting any work on your brakes, be sure to check the wheels are installed correctly.
What we’re looking for here is to have a solid on/off feel when engaging the brakes, and around 25-30mm between the brake lever and the handlebar after engaging it. This will give you enough room to effectively control and modulate your brakes on harder braking scenarios.
Basically all the major adjustments here will be done to the calliper position in relation to the rotor, allowing the disc to spin freely inside the calliper. Brake rub can slow you down, not to mention the very annoying noise you get on every wheel revolution.
With our hex key we’ll release both calliper mounting bolts just so the calliper position can be shifted. Then engage the brake and retighten the bolts lightly. This should relocate the calliper so the rotor is centered between the pads, but most times we’ll still need to perform some fine position adjustments. Once we’ve found the sweet spot we can then torque both mounting bolts to 7Nm.
Even if you’re mechanically inclined, a bent brake rotor will make this job a lot more challenging. As previously mentioned, we’re working towards positioning the calliper to obtain no rotor rub. Note that the clearance inside the pads is quite small, because of that the rotor alignment is critical.
Aligning the rotor may sound like a simple task but it takes years of practice to master. See, rotors from different manufacturers will behave differently when lateral force is applied, and it takes the correct amount of force on the correct spot to align a rotor back to its original shape. Not to mention examining the fault and determining the correct location and direction the force should be applied. If you happen to have bent rotors, we will also recommend paying a visit to your local bike shop.
And this is how to adjust your disc brakes. Make sure to do a few test runs and progressively experiment harder braking to ensure you’re happy with the adjustments and most importantly, safe to go on riding your bike under normal conditions.
For more fine adjustments guides, check out our Workshop Series. Make sure to enjoy your time maintaining your bike as much as you do riding it, and happy riding!
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