SHIMANO BR-CT91

Shimano BR-CT91 Altus Cantilever Brake Instruction Manual

Model: BR-CT91 (EBRCT91MFSA)

1. Introduction

This manual provides detailed instructions for the installation, operation, and maintenance of your Shimano BR-CT91 Altus Cantilever Brake. The BR-CT91 is a reliable cantilever brake system designed for bicycles, featuring standard brake pads and durable aluminum construction. It includes adjustable brake toe and spring tension for optimal performance.

Please read this manual thoroughly before attempting installation or use to ensure proper function and safety.

2. Safety Information

  • Always wear appropriate safety gear, including eye protection, during installation and maintenance.
  • Ensure all bolts are tightened to the manufacturer's specified torque settings. Overtightening or undertightening can lead to component failure.
  • Regularly inspect brake pads for wear and replace them when necessary. Worn pads reduce braking effectiveness.
  • Check brake cables for fraying or damage. Replace damaged cables immediately.
  • Test brakes thoroughly before riding. Ensure both front and rear brakes engage smoothly and provide adequate stopping power.
  • Consult a professional bicycle mechanic if you are unsure about any installation or adjustment procedures.

3. Package Contents

The Shimano BR-CT91 Altus Cantilever Brake package typically includes the following components:

  • Cantilever Brake Arms (left and right)
  • Brake Pads (standard type)
  • Straddle Wire
  • Brake Fixing Bolts and Washers
  • Spring Tension Adjusters

Note: Specific contents may vary slightly. Please verify all components are present before beginning installation.

4. Setup and Installation

Proper installation is crucial for safe and effective braking. Follow these steps carefully:

4.1 Attaching Brake Arms

  1. Clean the cantilever brake bosses on your bicycle frame or fork.
  2. Apply a thin layer of grease to the brake boss studs.
  3. Place the brake arms onto the bosses, ensuring the spring is correctly seated in one of the three holes on the boss (typically the middle hole for initial setup).
  4. Secure each brake arm with its respective fixing bolt and washer. Do not fully tighten yet.

4.2 Installing Brake Pads

  1. Insert the brake pads into the brake arms. Ensure the curved surface of the pad faces the rim.
  2. Adjust the brake pads so they are centered on the rim's braking surface and are parallel to the rim when engaged.
  3. Set the brake pad toe-in: The front edge of the pad should touch the rim slightly before the rear edge. This helps prevent squealing. A small piece of cardboard or a business card can be used as a spacer at the rear of the pad during tightening.
  4. Tighten the brake pad fixing bolts securely.

4.3 Connecting the Straddle Wire and Brake Cable

  1. Attach the straddle wire to the brake arms. One end typically hooks into a small hole on one arm, and the other end passes through a barrel adjuster on the other arm.
  2. Route the main brake cable from the brake lever through the cable housing and then through the cable hanger (if applicable) and the straddle wire's cable clamp.
  3. Pull the brake cable taut, ensuring the brake pads are approximately 2-3mm from the rim.
  4. Secure the brake cable firmly with the cable clamp bolt.
Shimano BR-CT91 Altus Cantilever Brake installed on a bicycle fork

Figure 1: Shimano BR-CT91 Altus Cantilever Brake assembly. This image shows the brake arms, pads, and straddle wire, illustrating the general appearance of the brake system when installed.

4.4 Adjusting Spring Tension

The BR-CT91 features adjustable spring tension to ensure both brake arms return evenly and quickly after braking.

  • If one brake arm is closer to the rim than the other, adjust the spring tension screw on the side that needs more tension (to pull it away from the rim) or less tension (to allow it to move closer).
  • Turn the small screw located near the brake boss on each arm. Turning clockwise increases tension, counter-clockwise decreases it.
  • Adjust until both pads are equidistant from the rim and retract smoothly.

5. Operating Instructions

To operate the Shimano BR-CT91 Altus Cantilever Brake:

  • Squeeze the brake lever on your handlebars. This pulls the brake cable, which in turn pulls the straddle wire, causing the brake arms to pivot inward.
  • The brake pads will contact the rim, creating friction and slowing or stopping the bicycle.
  • Release the brake lever to allow the springs to pull the brake arms and pads away from the rim.

Ensure your brake levers are easily accessible and provide comfortable reach for effective braking.

6. Maintenance

Regular maintenance ensures the longevity and optimal performance of your brakes.

  • Cleanliness: Keep brake pads and rim braking surfaces clean and free of dirt, oil, or grease. Use a clean cloth and rubbing alcohol if necessary.
  • Pad Wear: Inspect brake pads regularly for wear indicators. Replace pads when they are worn down to the wear line or if they become hardened or glazed.
  • Cable Condition: Check brake cables and housing for fraying, kinks, or corrosion. Lubricate cables periodically with a light lubricant designed for bicycle cables. Replace damaged cables and housing promptly.
  • Pivot Points: Ensure the brake arms pivot freely on their bosses. Apply a small amount of grease to the pivot points if movement becomes stiff.
  • Bolt Tightness: Periodically check all fixing bolts (brake arm bolts, pad bolts, cable clamp bolt) for proper tightness.

7. Troubleshooting

Problem Possible Cause Solution
Brakes squeal loudly Incorrect pad toe-in, glazed pads, dirty rim, loose components. Adjust pad toe-in, clean pads/rim, replace pads, check bolt tightness.
Poor stopping power Worn pads, contaminated pads/rim, loose cable, incorrect pad alignment. Replace pads, clean pads/rim, re-tension cable, adjust pad position.
Brake arms do not retract fully Insufficient spring tension, sticky pivot points, stiff cable/housing. Adjust spring tension, lubricate pivot points, replace cable/housing.
One brake arm rubs the rim Uneven spring tension, bent brake arm. Adjust spring tension screws, inspect for damage.

8. Specifications

Model Number:
BR-CT91 (EBRCT91MFSA)
Brand:
SHIMANO
Material:
Aluminum
Color:
Silver
Style:
Cantilever Brakes
Product Dimensions:
4.5"L x 4"W
Item Weight:
8.16 ounces
UPC:
689228011311
Manufacturer:
Shimano

9. Warranty and Support

9.1 Manufacturer's Warranty

This Shimano BR-CT91 Altus Cantilever Brake is covered by a Limited Warranty provided by the manufacturer, Shimano. For specific terms, conditions, and duration of the warranty, please refer to the documentation included with your purchase or contact Shimano customer support directly.

9.2 Customer Support

For technical assistance, replacement parts, or warranty claims, please contact Shimano customer support. Contact information can typically be found on the official Shimano website or in the product packaging.

Note: The legal disclaimer provided in the product information (1309905(116-117)9/10 50623(5:5/25/23:ARI 53023(10:6/1/23:ari60523(20:6/7/23:ari 70523(15:7/10/23:ari 91123(10:9/13) is an internal tracking code and does not contain consumer-facing legal information.

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