Troubleshooting Your Bike's Most Important Component
Disc brakes are a marvel of engineering, but even the best systems need occasional adjustment. From annoying sounds to inconsistent performance, many common issues can be fixed at home with a few simple tools. This guide will walk you through troubleshooting and fixing the top three problems we see in our workshop.
Tools You'll Need
For most of these adjustments, you won't need a full workshop. Here's a short list of essentials:
- A set of metric Allen (Hex) keys (usually 4mm and 5mm)
- A Torx T25 key
- Isopropyl alcohol
- A few clean rags
- A brake piston press or a sturdy plastic tire lever
Problem #1: Brake Rub - The Constant "Shing-Shing" Sound
A rubbing brake rotor is the most frequent issue riders face. It's caused by the brake caliper being misaligned with the rotor. The fix is simple and is often called "re-centering the caliper."
Step-by-Step: How to Center Your Brake Caliper
- Loosen the Caliper Bolts: Using your Allen or Torx key, slightly loosen the two main bolts that attach the brake caliper to your frame or fork. You only need to loosen them a quarter-turn—just enough so the caliper can wiggle from side to side.
- Squeeze the Brake Lever: Firmly squeeze and hold the corresponding brake lever. This action will force the brake pads to clamp down on the rotor, automatically centering the caliper body over the rotor.
- Tighten the Bolts: While still holding the brake lever firmly, carefully and evenly tighten the two caliper bolts. Tighten them incrementally, alternating between the top and bottom bolt, until they are snug.
- Check Your Work: Release the brake lever and spin the wheel. It should now spin freely without any rubbing sounds.
Problem #2: Squealing Brakes - The Annoying Howl
Squealing or howling brakes are almost always caused by contamination of the brake pads or rotor. This happens when oils (from your hands, chain lube, or sprays) get onto the braking surface.
Step-by-Step: How to Decontaminate Your Brakes
- Remove the Wheel: Take the wheel out of the bike.
- Clean the Rotor: Thoroughly spray a clean rag with isopropyl alcohol and vigorously wipe down both sides of the brake rotor until it is perfectly clean. Do not touch the braking surface with your fingers.
- Inspect and Clean the Pads: Remove the brake pads from the caliper. If they look dark, shiny, or oily, they are contaminated. You can try to save them by lightly sanding the surface with fine-grit sandpaper to expose fresh pad material, then cleaning them with isopropyl alcohol. However, for best results, we recommend replacing contaminated pads.
- Reassemble and Bed-In: Reinstall the pads and the wheel. It's a good idea to "bed-in" the clean pads by doing a few hard, controlled stops to transfer a fresh layer of pad material to the rotor.
Problem #3: Soft or Spongy Lever Feel
If your hydraulic brake lever feels soft, pulls all the way to the handlebar, or has inconsistent power, it's a sign that there is air in the hydraulic system. This is a serious safety issue that needs to be addressed.
The Solution: A Hydraulic Brake Bleed
Fixing a spongy lever requires a **brake bleed**, which is the process of pushing new hydraulic fluid through the system to force out any trapped air bubbles. While this can be done at home with a specific bleed kit for your brake model (e.g., SRAM or Shimano), it is a more advanced procedure that can be messy and frustrating if done incorrectly.
When to Seek Professional Help
While the adjustments above are great skills to have, your safety is paramount. A full hydraulic brake bleed is a service that is often best left to professional mechanics to ensure it's done perfectly. If you've tried these fixes and still have issues, or if you're not comfortable bleeding your own brakes, our expert team is here to help.
We offer a full range of professional services to get your bike stopping safely and silently again. Learn more on our Wheel Repair & Service Page.