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Custom Electric Bike Factory since 2010.
Have you ever found yourself in the awkward situation where your bike brakes squeal, the disc wobbles, or the wheels seem to engage on their own while rolling? While a bike shop technician friend can help, learning these skills can make you a sought-after companion for fellow riders. Mike Perejmybida, the Technical Maintenance Manager at Squire John Ski & Bike Shop in Ontario, Canada, with over a decade of bike repair experience, shares brake adjustment insights to empower you to handle these situations on your own.
I. Adjusting Disc Brakes
Firstly, ensure the wheel assembly is correct. While hub-based wheel assemblies are usually fine, quick-release wheel systems may need special attention. Ensure the bike is upright or on a maintenance stand to confirm proper wheel alignment without tilting.
If there's any friction on the disc, start by loosening the brake caliper fixing screws, squeeze the brake lever to engage the disc, and then tighten the caliper screws. This step ensures the caliper is centered, resolving about 75% of disc brake adjustment issues.
If there's still friction, observe the disc while spinning the wheel to identify if the issue lies in disc wobbling or uneven brake pad contact. If the disc has slight deformation, use a PARKTOOL disc straightening tool to gently straighten it. Caution is advised as discs are fragile. For more complex adjustments, seeking guidance from a technician while observing can help build your experience.
Check if your brake pads need replacement: If the spring plates on the brake pads seem close to the disc or if the caliper pistons are significantly pushed out, it's time for new pads.
Replacing them is simple: Most brake pads are fixed via a retaining pin passing through holes in the pads. Remove the pin, take out the old pads, use a wide flathead screwdriver to gently push the caliper pistons back to make space for the new pads to avoid immediate friction.
If the brake suddenly feels too tight or too soft or if one caliper piston gets stuck, it might be time to change the brake fluid. This is a more intricate process, akin to changing oil in a car, and might require professional assistance, like your technician friend, as it involves bleeding and refilling the brake fluid, often part of routine maintenance.
II. Rim Brake Adjustment
Despite the rise in popularity of disc brakes, rim brakes remain prevalent, especially in the road cycling sphere. Their simple construction makes them easier to adjust.
1. Centering the Brake
Ensure equal clearance between brake pads and the rim on both sides. Before adjustment, secure the brake and frame fixing screws. Check if the brake arms are centered, making simultaneous contact with the rim during braking. Adjust the centering screw on the brake arms to achieve this, observing wheel response while adjusting.
2. Fine-Tuning Brake Pads
Loosen the brake pad holder screw and move the pads up or down along the brake arm's groove to align their height with the rim's braking surface. Rotate the pads to align the curved edge with the upper edge of the rim's braking surface. Tighten the pad screw after adjusting, ensuring the pads don’t contact the tire, which could cause a blowout.
Advanced brake pad holders allow multidirectional adjustments for parallel alignment with the rim and customizable toe-in, enhancing braking performance by adjusting the pads' front and rear contact points by about 1mm if there's sharp noise or stickiness during braking.
3. Adjusting Brake Reach
If the brake feels too loose or requires significant lever pull, adjust the reach screw or the fine-tuning screw on the brake lever to customize the lever's distance from the handlebar and the brake engagement, matching your preferences. If these adjustments are insufficient, slightly tighten the brake cable.
Tips: In races, if you notice rim brake contact or friction, you can adjust it using the quick-release lever next to the brake to eliminate friction temporarily. However, post-ride, tighten the quick-release lever and readjust as needed.
When to Seek Professional Help: If the wheel still rubs against the brakes after adjustments, it might not be a brake adjustment issue but a wheel truing problem. In such cases, it's best to consult a technician for assistance.
III. Cantilever Brake Adjustment
Cantilever brakes, often seen on off-road and touring bikes, offer a different challenge due to their linkage mechanism between brake levers and independent brake arms.
They require meticulous adjustment of pad width, height, parallel alignment, and toe-in for optimal performance. Seek assistance from experienced technicians to address these complexities.
Bonus Tip: Pay attention to brake cables exposed to the environment, as they wear over time. If braking feels rough or deteriorates, consider replacing the cables rather than just adjusting the brakes.
Given the limited audience for bikes equipped with cantilever brakes, further details are omitted here. If you're interested, feel free to comment, and I might dedicate a separate section to cantilever brakes.
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