How to Adjust a Bicycle Brake (Rim & Disc Brakes)

Your brakes are rubbing against the rim, or they’re too loose and not stopping effectively. Maybe one brake pad is closer to the rim than the other, or the brake lever feels mushy.

Adjusting bicycle brakes is a basic maintenance skill that every cyclist should know. The process differs between rim brakes and disc brakes, but both are straightforward once you understand the adjustment points.

In this guide, I’ll walk you through adjusting both rim brakes (caliper, cantilever, V-brakes) and disc brakes (mechanical and hydraulic), including common issues and how to fix them.

Types of Brakes: Quick Identification

Before adjusting, identify your brake type:

Rim Brakes

• Caliper Brakes: Single pivot, common on road bikes
• Cantilever Brakes: Two separate arms, older mountain bikes
• V-Brakes: Linear-pull brakes, modern mountain bikes and hybrids

Disc Brakes

• Mechanical Disc: Cable-actuated, uses brake cable
• Hydraulic Disc: Fluid-actuated, uses brake fluid

Adjusting Rim Brakes

Tools Needed

• Allen wrenches (usually 4mm, 5mm)
• Adjustable wrench (for cable anchor bolts)
• Optional: Cable cutters (if replacing cable)

Step 1: Check Brake Pad Alignment

Before adjusting cable tension, ensure brake pads are aligned:

1. Check pad position: Pads should hit the rim squarely, not the tire or below the rim
2. Adjust pad angle: Loosen the pad bolt, position the pad, then tighten
3. Check both sides: Both pads should contact the rim at the same time

Step 2: Adjust Cable Tension

If brakes are too loose (not stopping effectively):

1. Locate the barrel adjuster: Found on the brake lever or brake caliper
2. Turn counterclockwise: This increases cable tension (tightens brakes)
3. Test: Squeeze brake lever and check stopping power
4. Fine-tune: Adjust until brakes engage about 1/3 of the way through lever travel

If brakes are too tight (rubbing):

1. Turn barrel adjuster clockwise: This decreases cable tension (loosens brakes)
2. Test: Spin the wheel to check if rubbing stops
3. Fine-tune: Adjust until pads are close but not touching

Step 3: Center the Brakes

If one pad is closer than the other:

For Caliper Brakes:

1. Loosen the center bolt: The bolt that holds the brake to the frame
2. Center the brake: Move the brake so both pads are equidistant from the rim
3. Tighten the center bolt: Hold the brake centered while tightening

For V-Brakes:

1. Use the balance screw: Small screw on one brake arm (usually marked ”+” and ”-”)
2. Turn clockwise: Moves that pad away from rim
3. Turn counterclockwise: Moves that pad toward rim
4. Adjust until centered: Both pads should be equidistant

Step 4: Adjust Pad Clearance

Ideal clearance: Pads should be 1-2mm away from the rim when not braking.

To adjust:

1. Use barrel adjuster: Fine-tune cable tension
2. Check both sides: Ensure equal clearance on both pads
3. Test: Brakes should engage smoothly without excessive lever travel

Adjusting Disc Brakes

Mechanical Disc Brakes

Tools Needed:

• Allen wrenches (usually 4mm, 5mm)
• Disc brake pad spacer (optional, for pad retraction)

Step 1: Adjust Cable Tension

1. Locate barrel adjuster: On brake lever or caliper
2. Turn counterclockwise: Increases tension (tightens brakes)
3. Turn clockwise: Decreases tension (loosens brakes)
4. Test: Adjust until brakes engage properly

Step 2: Center the Caliper

If brake is rubbing:

1. Loosen caliper mounting bolts: Two bolts that hold caliper to frame
2. Squeeze brake lever: Hold it tight
3. Tighten bolts: While holding lever, tighten bolts evenly
4. Release lever: Caliper should now be centered

Step 3: Adjust Pad Clearance

1. Use pad adjustment screw: Usually on the caliper
2. Turn to move pads: Adjust until proper clearance
3. Test: Brakes should not rub when wheel spins

Hydraulic Disc Brakes

Tools Needed:

• Allen wrenches (usually 4mm, 5mm)
• Bleed kit (if brakes need bleeding)

Step 1: Center the Caliper

1. Loosen caliper bolts: Two mounting bolts
2. Squeeze brake lever: Hold tight
3. Tighten bolts: While holding lever, tighten evenly
4. Release lever: Caliper should be centered

Step 2: Adjust Lever Reach

Many hydraulic brakes have a reach adjustment:

1. Locate reach adjuster: Small dial or screw on brake lever
2. Turn to adjust: Moves lever closer or farther from handlebar
3. Set to preference: Adjust for comfortable hand position

Step 3: Bleed Brakes (If Needed)

If brakes feel spongy or weak:

1. Check brake fluid level: May need topping off
2. Bleed the system: Removes air bubbles
3. Follow manufacturer instructions: Each brand has specific procedure
4. Consider professional help: Bleeding can be complex

Note: Hydraulic brake adjustment is usually limited to centering and lever reach. If brakes are weak, they likely need bleeding or pad replacement.

Common Brake Issues and Fixes

Brakes Rubbing

Cause: Pads too close to rim/rotor, misaligned caliper, or bent rim

Fix:

1. Check rim/rotor: Ensure it’s straight (not bent)
2. Center caliper: Adjust caliper position
3. Loosen cable tension: Use barrel adjuster
4. Check pad clearance: Ensure proper spacing

Brakes Too Loose

Cause: Worn pads, stretched cable, or insufficient cable tension

Fix:

1. Check pad wear: Replace if worn down
2. Increase cable tension: Turn barrel adjuster counterclockwise
3. Check cable: May need replacement if stretched
4. Adjust pad clearance: Move pads closer to rim/rotor

One Pad Closer Than Other

Cause: Misaligned caliper or uneven pad wear

Fix:

1. Center caliper: Adjust caliper position
2. Check pad alignment: Ensure pads are positioned correctly
3. Replace pads: If one is more worn than the other
4. Balance adjustment: Use balance screw (V-brakes) or center bolt (caliper)

Brake Lever Goes to Handlebar

Cause: Worn pads, air in hydraulic system, or cable stretch

Fix:

1. Check pad wear: Replace if worn
2. Bleed brakes: If hydraulic (removes air)
3. Tighten cable: Increase cable tension
4. Check for leaks: Hydraulic brakes may have fluid leaks

Brakes Squealing

Cause: Dirty pads/rotor, contaminated pads, or misalignment

Fix:

1. Clean pads and rotor: Use isopropyl alcohol
2. Check for contamination: Oil or grease on pads
3. Realign pads: Ensure proper contact
4. Replace pads: If contaminated or worn

Safety Check After Adjustment

After adjusting brakes, always:

1. Test brakes: Squeeze levers firmly
2. Check stopping power: Brakes should stop effectively
3. Check clearance: Pads should not rub when not braking
4. Test both brakes: Front and rear should work independently
5. Ride test: Test at low speed before normal riding

When to Seek Professional Help

Consider professional help if:

• Hydraulic brakes need bleeding: Complex procedure
• Brakes still not working: May need pad replacement or cable replacement
• Bent rim or rotor: Requires truing or replacement
• Uncertain about adjustment: Safety is priority
• Brake lever feels spongy: May indicate air in system or leaks

Bicycle Brake Adjustment FAQs

Summary: Regular Adjustment Keeps You Safe

Adjusting bicycle brakes is a straightforward skill that ensures your safety on every ride. Whether you have rim brakes or disc brakes, understanding the adjustment points helps you maintain proper stopping power and prevent issues.

Key Takeaways:

• Identify brake type before adjusting (rim vs disc, mechanical vs hydraulic)
• Check pad alignment and wear before adjusting tension
• Use barrel adjuster for fine-tuning cable tension
• Center caliper if pads are rubbing or misaligned
• Test brakes after adjustment before riding
• Seek professional help for complex issues (bleeding, bent components)

Regular brake maintenance and adjustment keeps your bike safe and ensures reliable stopping power when you need it most.