Caliper Brakes

This system consists of caliper brakes (Figure 1). With this system, the lever is connected to the brake by a cable. By squeezing the lever, pressure is applied to the wheel rim by brake pads. This slows the rotation of the wheel, which slows the bicycle.

This system consists of several parts:

Read the Warning about Mechanical Work before performing any mechanical work on your bicycle.

Never use rims designed specifically for disc brakes. Rim brakes require a flat sidewall on the rim for proper braking action.

The brake can easily be opened if needed.

Since the brake levers are part of this system, also read about brake levers on your bicycle:

caliper_brake.gif

FIGURE 1:

Caliper brake

INSPECTION

Before every ride squeeze the brake lever firmly. It should not be possible to pull the lever fully to the handlebar. When the brakes are not applied, the brake pads should be 1-2mm from the rim. Brake pads should be aligned with the rim surface (Figure 2). If your brakes are too tight, too loose, or not centered on the rim, adjust them before riding the bicycle.

Figure 2 shows toe-in, an angular alignment of the brake pad, which can be adjusted to prevent squealing of the brakes. Used brake pads, or some new direct-pull type brakes, may not require toe-in.

Every month check the brake cables on your bicycle for kinks, rust, broken strands, and frayed ends, and check the housing for bent ends, cuts, stretched coils, and wear. Replace any part which does not pass inspection.

Every month inspect the brake pads on your bicycle for wear. Brake pads have shallow grooves in their braking surface. If any of these grooves are less than 2 mm deep, replace the pads.

Every 3 months tighten the bolts on the caliper brakes to the torque specifications.

If your bicycle has carbon fiber composite rims, only use Bontrager Carbon Rim brake pads, or a similar product. Carbon rims may cause premature wear of standard brake pads, and may not perform properly in wet conditions or in severe brake applications without the correct brake pads.

brake_pad_alignment_b.gif

FIGURE 2:

Brake pad alignment

ADJUSTMENT

To adjust brake pad clearance to the rim

  1. Turn the barrel adjuster. To increase the pad clearance, turn the barrel adjuster in (clockwise)To reduce the pad clearance, turn the barrel adjuster out (counter-clockwise). For most caliper systems, the barrel adjuster is on the brake itself.
  2. If the brake pads cannot be adjusted properly in this manner, loosen the cable clamp bolt and re-attach the cable as explained in To install a brake cable, but without removing the brake cable.

To adjust the alignment of the brake pads

  1. Loosen the brake pad fixing bolt.
  2. Follow the procedures in Inspection to align and tighten the brake pads.
  3. After the brakes are adjusted, test the brakes. Apply maximum braking force to the levers. Ensure the cable does not slip, the pads close toward the rim at right angles, and the pads do not contact the tire.

LUBRICATION

Every 3 months lubricate your brake arm fixing pivots with a light chain oil or a similar light oil.

Whenever a cable is replaced, lubricate the cable with a thin layer of synthetic bicycle grease or a similar lubricant.