How to install disc brake

Avid's mechanical disc brakes occupy a large market share and have a good reputation among users. The 2007 Avid mechanical disc brake has two models, namely bb7 and bb5.

I. Basic information

Required tools

2.5mm Allen wrench (hexagon wrench)

T-25 wrench

Cable cutter

Torque wrench, range 2.8- 10 [newtonm] (25-90 in-lb).

Protective glasses

Caliper configuration system

Avid disc brakes use an assembly system called Caliper Positioning System (CPS). The stacking of these concave-convex washers enables the caliper and the brake disc to be accurately calibrated without worrying about the tolerance between the front fork and the frame mounting bracket, so that the contact of the brake pad is perfect and straight.

Figure 1 safety information

The effectiveness of braking depends on many factors, including vehicle speed, ground type and conditions, braking force, correct installation and maintenance of brakes, brake pipes, brake oil, hand brakes, brake pads, vehicle condition, cyclist's weight, correct braking technology, weather, terrain and many other factors.

Remember, you need a longer braking distance in wet conditions. In order to reduce possible accidents and minimize wear, it is necessary to avoid wheel locking.

Side-pull brake handles are needed to match the disc brakes, such as Avid's speed dial series and FR5 brake handles.

Disc brakes are compatible with international standard wheels with 44 mm and 6 bolts.

It is recommended to use 32-hole or 36-hole (spoke) rims with 3x or 4x cross spoke lace patterns. Do not use radial spoke wheels.

Disc brakes are sensitive to oil! Do not spray any solvent or lubricant near the brake disc and brake pad. Never touch the surfaces of brake pads and brake discs with your fingers. Doing so will greatly reduce the braking performance.

Do not touch the surface of the brake part of the brake disc with your hands, put on gloves, or grasp the spokes to handle the brake disc. The oil on your hand will reduce the performance of the disc brake.

Disc brakes can be very hot during use. Do not touch the brake caliper and brake disc immediately after use. Before making any adjustment, make sure that the disc brakes have cooled down.

Two. device

(1). Install the rotor.

Install the brake disc on the wheel hub with the provided T-25 screw and lock it with a torque of 6.2 Nm (55 in. lb). The side with the trademark logo of Avid must be outside. When finished, install the wheels on the front fork and the frame.

Figure ii

Warning:

If you use a removable gasket for your flower drum, you need a longer disc fixing screw. Please contact the wheel hub manufacturer for the recommended screw length.

(2) Install the front caliper.

Install the front brake caliper to the front fork.

There are two ways to install the front fork, one is the international standard installation, and the other is the column installation.

International standard installation (stainless steel installation)

Loosen the CPS screw and install the brake caliper on the mounting tab. The locking torque is 9- 10 nm (80-90 in-lb). Check whether the CPS part of the brake caliper can move freely.

Figure 3

Post-installation

Remove the mounting bracket, leaving the CPS screw and washer set. Install the caliper directly to the front fork. After tightening the screw, turn it backwards by 1/8 to 1/4 turns. Check whether the CPS part of the brake caliper can move freely.

Figure 4

(3) Install the rear caliper.

Loosen the CPS screw and install the rear caliper on the disc brake bracket of the frame. Tighten with a torque of 5-7 Nm (40-60 in-lb). Check whether the CPS part of the brake caliper can move freely.

Figure 5

4). Install the brake cable

Pass the brake line through the fixing screw on the operating arm. Tighten the thread with a tool and don't loosen it. Be careful not to push the torque arm forward when pulling the cable. Tighten the fixing screws with a torque of 5-7 Nm (40-60 in-lb). Use the cylinder adjuster on the brake lever to tighten the brake line (if necessary).

Important: After fixing the brake pipe, make sure that the pipe does not exceed 20mm (3/4 inch). Please cut off the extra thread.

Figure 6

Bb7 and bb5 have some special settings respectively.

bb7

After fixing the brake pipe, move the lower sheath downward and add a small amount of light grease to it. After that, put the catheter back in its original correct position.

Figure 7

bb5

Before installing the pipeline, make sure that the barrel regulator is completely screwed in.

Figure VIII

(5) Align the calipers.

bb7

The ideal ratio of the disk to the outside of the rotor slot is 1/3 and 2/3.

Figure 9

1 Turn the inner knob clockwise (close to the wheel) until the brake disc is in the correct position of the caliper body. Note that the brake disc is not in the center of the caliper.

Figure X

2 Turn the outer knob until it tightly presses the brake disc and the inner brake pad together to fix the drive arm. Now the caliper is in the best position and can be locked. After a while, the brake pads were unscrewed.

Figure Xi

3 Lock the two CPS screws at this time. Lock the spare ones in turn until the torque reaches 8- 10Nm(70-90in-lb).

Figure XII

bb5

Turn the adjusting knob until the brake disc is in the center of the caliper.

Figure XIII

1 Turn the internal adjustment knob clockwise with your fingers or T-25 wrench until the brake disc is in the center of the caliper. Start the next installation from this position.

Figure XIV

2 Make sure that the CPS screw is loose enough so that the caliper can move freely.

3 Hold the brake lever and press the brake pad tightly on the brake disc.

4 Keep the brake lever in this state and tighten the CPS screw to 8- 10 [newtonm] (70-90 in-lbs). After locking, release the brake lever.

Figure XV

(6) Adjust the gasket.

bb7

Turn the two brake pad adjustment knobs counterclockwise until the brake pad and brake disc reach the required clearance, about 2 or 3 graduations on each side.

Figure XVI/XVII

Important information:

For the slack of the brake pipe, only the cylinder adjuster on the brake lever is used for adjustment. For the pull rod, use the adjustment knob on the outside. For the adjustment of brake pad wear, use both internal and external knobs to adjust.

bb5

Turn the adjusting knob counterclockwise until the disc rotates smoothly. Screw in and out to get the state you want. Of course, you can't let the CD feel procrastinating. If you can't get the feeling you want, or the disc is dragging, please repeat step 5.

Figure XVIII

Three. fine-tune

Check before each ride

Check the wear of the brake line.

Squeeze the brake lever hard to check whether the brake works normally. If necessary, adjust brake pad wear.

Check the wear of brake pads and replace them if necessary.

Make sure the plates are clean and free from sundries and oil stains.

Brake line slack adjustment

By adjusting the barrel adjuster on the brake lever, the slack problem of the brake line can be solved. Turn the adjuster outward until the thread is no longer loose, but not so far that the caliper torsion arm moves forward. It should be noted that when the brake lever is released, the torsion arm should be completely reset. If necessary, repeat step 6.

Figure XIX

Note: The new brake line will lengthen and need to be adjusted.

Brake pad running-in

It takes about 20 to 40 full brakes to break in the brake pads. After the first ride, you will start to notice the increase in braking force. Braking noise is not only produced in the running-in period, but also in the whole life cycle of brake pads. Noise depends on many factors, such as brake installation, rider's weight, riding type, brake type and riding conditions (such as dust, soil, surface pollution friction, etc.). ).

Clean (clean)

Pay special attention when cleaning bicycles and brakes. General use does not require cleaning calipers, brake discs and brake pads. When cleaning, only use water and dish cleaning agent to clean calipers and dishes, and be sure to clean the residual cleaning agent on the dishes. Then dry it with a clean paper towel.

Sprint tension adjustment

If necessary, you can adjust the spring tension by turning the elastic adjustment screw with a 2.5mm Allen wrench. Turning the screw clockwise can enhance the elasticity, which is equivalent to squeezing the brake lever.

bb7

Figure 20

bb5

Figure XXI

Brake pad wear adjustment

bb7

As time goes on, you need to solve the problem of brake pad wear. You can make simple adjustments in two steps.

Turn the two red adjustment knobs clockwise inside and outside, and turn one or two scales as needed to return the brake to the best setting. Do not adjust the cylinder adjuster on the brake lever.

Figure XXIII/XXIII

There is a pad wear indicator in the center of each knob. As the knob advances, the indicator will retract to the depth of the knob, so that the general wear of the brake pad can be seen.

When the total thickness of the brake pad (including the back plate and friction material) is less than 3mm, it needs to be replaced.

bb5

As time goes on, you need to solve the problem of brake pad wear. You can make simple adjustments in two steps.

1 Turn the cylinder adjuster on the caliper counterclockwise. After adjustment, make sure that the lock nut is locked, as shown below:

Figure XXIV

Turn the adjustment knob on the inside clockwise.

Figure XXV

These two steps bring the brake pad closer to the disc. As long as there is wear, both brake pads need adjustment. Try different settings to get the effect you need.

Note: Although you can make similar adjustment through the barrel adjuster on the brake lever, we still recommend that you make adjustment at the caliper end. The adjuster on the brake lever is used to adjust the slack of the rope.

Replace brake pads.

bb7

1 When the overall thickness of the brake pad (including liner and friction medium) is less than 3mm, it needs to be replaced.

Turn the two adjustment knobs counterclockwise until they are outermost. Hold the entire brake pad assembly and pull out both brake pads at the same time.

Figure XXVI

Assemble the left and right new brake pads and clips together.

Figure XXVII

3 Squeeze the assembly with your fingers.

Figure XXVIII

4 Clamp the assembly together and insert it into the caliper. Push steadily until it clicks into place.

Figure XXIX

The brake pad marked "R" is on the spoke side of the brake.

bb5

When the overall thickness of the brake pad (including lining and friction medium) is less than 3mm, it needs to be replaced.

Figure 30

1 Remove the old brake pads. Turn the inner adjustment knob counterclockwise until it reaches the bottom. Pull out the elastic clip between the two brake pads, and then pull out the brake pads one by one.

2 Install new brake pads and combination clips. Insert the two brake pads into the caliper one by one.

Very important information:

Make sure that the black brake pad is placed on the inside (near the wheel) and the blue brake pad is placed on the outside (away from the wheel), and then slide the elastic clip into the position in the caliper-between the two brake pads.

If you are satisfied, please accept it. Thank you.