Spongy braking on Shimano’s BR-5700 [paid link] brake calipers—a trusted component in the 105 series—can be both alarming and dangerous. Riders expect precise stopping power and responsive modulation, and when those sensations are replaced with softness or lag, it’s a clear signal that something’s amiss in the system. This guide breaks down why your BR-5700 [paid link] brakes might feel spongy and provides a step-by-step method to fix it effectively.
Understanding the BR-5700 Brake Caliper
The Shimano BR-5700 [paid link] is a dual-pivot caliper brake designed for road bikes within the 105 10-speed groupset range. With symmetrical dual-pivot arms, these calipers provide strong braking performance and reliable modulation. However, because they are cable-actuated rim brakes, their feel is sensitive to cable tension, housing condition, pad alignment, and caliper centering.
Common Causes of Spongy Braking on the BR-5700
A “spongy” feeling in road bike brakes generally refers to a lack of immediate braking response or a mushy lever feel. The causes for this sensation in BR-5700 brakes include several setup and maintenance issues:
Cable Stretch or Improper Tension
Newly installed cables tend to stretch after initial use, causing slack that reduces braking response. If the inner cable isn’t properly tensioned, the lever will travel further before the pads engage the rim.
Housing Compression and Friction
Aged or poorly installed brake housing may compress under braking force or introduce excess friction. Both conditions delay pad engagement and absorb lever input before reaching the caliper.
Brake Pad Wear or Improper Alignment
Worn pads reduce contact area, while misaligned pads may contact the rim unevenly. In both scenarios, the lever must be pulled further to engage full braking force.
Caliper Arm Resistance or Pivot Corrosion
The BR-5700’s dual-pivot arms must move freely. If corrosion or dirt accumulates at the pivot points, the arms resist smooth movement, requiring more force at the lever.
Under-Torqued Mounting Bolts or Uncentered Calipers
A loosely mounted caliper can flex during braking, and if the brake arms aren’t centered over the rim, pad engagement becomes inconsistent, leading to vague feedback at the lever.
How to Fix Spongy BR-5700 Brakes: Step-by-Step Guide
Once you understand the source of the problem, restoration of crisp, responsive braking becomes straightforward. The steps below will guide you through a full assessment and adjustment process.
Check and Retension Brake Cables
Start by inspecting the brake cable from lever to caliper. If it appears stretched or slack, release the cable anchor bolt on the caliper, pull the slack through, and re-tighten while applying slight brake lever pressure. This ensures appropriate tension under real-world conditions.
Inspect and Replace Worn Housing
Cable housing that appears kinked, frayed, or dry should be replaced. Choose compressionless housing for better response and pair it with stainless inner cables for smoother actuation. Lubricate all contact points with a light Teflon-based grease before reinstalling.
Realign and Reset Brake Pads
Remove the pads and check for wear. If they are uneven or worn past the wear line, replace them. When reinstalling, align each pad so its full surface contacts the rim, about 1mm from the braking surface with a slight toe-in to prevent squeal.
Center the Caliper Arms
Loosen the mounting bolt slightly and center the caliper over the rim using a 5mm hex key [paid link]. Tighten the bolt to the manufacturer’s torque spec (6–8 Nm) while maintaining alignment. Then fine-tune centering with the side adjustment screw.
Lubricate Pivot Points
Apply a drop of light oil to each pivot point on the caliper arm. Work the brake lever several times to distribute lubricant and restore smooth motion.
Check Lever Feel
After all adjustments are complete, squeeze the brake lever firmly. It should engage quickly and feel consistent throughout the pull. If there’s still excessive travel or mushiness, reassess cable tension and housing integrity.
Optimizing Performance for Long-Term Crispness
Preventing sponginess from returning means committing to regular maintenance. The following practices will help maintain optimal brake performance:
- Clean and inspect cables every 1,000–1,500 kilometers.
- Replace brake pads before wear lines disappear.
- Re-center calipers after wheel removals or crashes.
- Avoid overtightening barrel adjusters to prevent tension imbalances.
Additionally, consider upgrading to low-friction cable kits designed for road braking systems. These systems enhance responsiveness and reduce maintenance intervals, especially in wet or dusty conditions.
When to Consider Replacement or Professional Help
If, after completing the above steps, the brakes still feel inconsistent or weak, inspect the lever mechanism and brake caliper springs. In rare cases, internal lever wear or caliper spring fatigue may cause performance loss. At this point, consulting a professional mechanic or replacing the caliper may be the best course of action.
Conclusion
A spongy feel in Shimano BR-5700 brakes isn’t something to ignore. It’s often the result of multiple small issues—most of which are easily fixable with proper maintenance and adjustment. By methodically addressing cable tension, pad alignment, housing quality, and pivot function, riders can restore the braking feel to crisp, predictable performance.
Frequently Asked Questions (FAQs)
Q1: Why does my BR-5700 brake lever travel too far before braking starts?
This is usually due to cable slack or worn brake pads. Check for stretched cable or replace worn pads and reset alignment.
Q2: Can I use compressionless housing with BR-5700 brakes?
Yes, compressionless housing can improve responsiveness significantly but should be paired with smooth inner cables for best results.
Q3: What torque should I use when mounting the BR-5700 caliper?
Use a torque setting of 6–8 Nm when tightening the mounting bolt for secure and centered caliper installation.
Q4: My brakes are centered but still feel weak—what should I check next?
Inspect for corroded pivots, dry housing, or under-lubricated moving parts. These can all absorb energy before it reaches the brake pads.
Q5: How often should I replace the brake cables on BR-5700?
Depending on riding conditions, replace every 3,000–5,000 kilometers or if you notice increased lever travel or reduced power.
Q6: Can misaligned pads cause a spongy feel even if cable tension is correct?
Yes, if pads don’t make full, even contact with the rim, they delay engagement and reduce braking efficiency.