General Safety Information
In order to realize the best performance, we recommend that the following
combination be used.
Caliper
Brake Lever
Rotor
BR-M445/M446
BL-M445/T445
SM-RT53 (160mm)
SM-RT53M (180mm)
SM-RT53L (203mm)
SM-RT51
SM-RT51M
■ Installation of the brake lever (BL-M445/T445)
Secure the brake lever as shown in the illustration. (Check that the brake lever does not interfere
with the shifting lever during operation. Refer to the Service Instructions for the shifting lever also.
Some types might require the shifting lever to be installed first, due to the position of the shifting
lever fixing bolts.)
Brake lever Tightening torque:
6 - 8 N·m {53 - 69 in. lbs.}
Operate the brake lever several times and check whether the brakes operate normally or
not. Also check that there are no oil leaks visible.
For C-shaped guides and the
usual type of cable stoppers,
use the special Shimano
cable supporter (sold
separately) to secure as
shown in the illustration.
< C-shaped guide > < Usual type of cable stopper >
Tightening torque:
0.3 - 0.5 N·m {2.7 - 4.4 in. lbs.}
Cable Supporter
Mineral Oil
Brake pad unit
SM-HANG
Hose
SM-BH59
SM-DB-OIL
B01S (Resin pads)
Technical Service Instructions SI-8J50A-002
Disc Brake System
(For Cross-Country)
WARNING
• Please use extra caution to keep your fingers away from the rotating
disc brake rotor during installing or servicing the wheel. The rotor is
sharp enough to inflict severe injury to your fingers if caught within the
openings of moving rotor.
• The 203 mm and 180 mm rotors provide a higher braking force than the 160 mm rotors.
Make sure that you have a complete feel for the braking characteristics before using the
brakes.
• The calipers and rotor will become hot when the brakes are operated, so do not touch
them while riding or immediately after dismounting from the bicycle, otherwise you may
get burned. Check that the brake components have cooled down sufficiently before
attempting to adjust the brakes.
• The required braking distance will be longer during wet weather.
Reduce your speed and apply the brakes early and gently.
• If the road surface is wet, the tires will skid more easily. If the tires skid, you may fall off
the bicycle. To avoid this, reduce your speed and apply the brakes early and gently.
• Always make sure that the front and rear brakes are working correctly before you ride
the bicycle.
• Be careful not to allow any oil or grease to get onto the rotor and brake pads, otherwise
the brakes may not work correctly.
• If any oil or grease do get on the pads, you should replace the pads.
If any oil or grease gets on the rotor, you should clean the rotor. If
this is not done, the brakes may not work correctly.
• Before riding the bicycle, check that the thickness of each pad is 0.5
mm or more.
• If noise occurs when the brakes are operated, it may indicate that
the brake pads have worn down to their usage limit. After checking
that the brake system has cooled down sufficiently, check the brake
pad thicknesses.
Replace the brake pads if the pad wear indicators are visible.
• Vapor lock may occur if the brakes are applied continuously. To
relieve this condition, momentarily release the lever.
• Use only genuine Shimano mineral oil. If other types of oil are used, it may cause
problems with brake operation, and cause the system to be unuseable.
• Be sure to use only oil from a freshly-opened container, and do not re-use oil which has
been drained from the bleed nipple. Old oil or already-used oil may contain water which
could cause vapor lock in the brake system.
• Be careful not to let water or air bubbles to get into the brake system, otherwise vapor
lock may occur. Be particularly careful when removing the cover of the reservoir tank.
• If cutting the brake hose in order to adjust the length of the hose, or when changing over
the brake hose from left to right or vice versa, be sure to bleed the air from the hose by
carrying out steps (5), (8) to (10) given in “Adding mineral oil and bleeding air” in the
Service Instructions.
• When turning the bicycle upside down or on its side the brake system may have some
air bubbles inside the reservoir tank which are still there when the reservoir tank cover is
replaced, or which accumulate in various parts of the brake system when it is used for
long periods. This disc brake system is not designed to be turned upside down. If the
bicycle is turned upside down or on its side, the air bubbles inside the reservoir tank may
move in the direction of the calipers. If the bicycle is ridden in this condition, there is the
danger that the brakes may not operate and a serious accident could occur.
If the bicycle has been turned upside down or on its side, be sure to operate the brake
lever a few times to check that the brakes operate normally before riding the bicycle. If
the brakes do not operate normally, adjust them by the following procedure.
• If fluid leaks occur, immediately stop using the brakes and carry out the appropriate
repairs. If you continue riding the bicycle while fluid is leaking, there is the danger that
the brakes may suddenly stop working.
• If the quick release lever is on the same side as the rotor, there is the danger that it may
interfere with the rotor, so check that it does not interfere.
• It is important to completely understand the operation of your bicycle's brake system.
Improper use of your bicycle's brake system may result in a loss of control or an
accident, which could lead to severe injury. Because each bicycle may handle
differently, be sure to learn the proper braking technique (including brake lever pressure
and bicycle control characteristics) and operation of your bicycle. This can be done by
consulting your professional bicycle dealer and the bicycle's owners manual, and by
practicing your riding and braking technique.
• If the front brake is applied too strongly, the wheel may lock and the bicycle may
fall forward, and serious injury may result.
• The M445/M446 disc brakes are designed for optimum performance when
used in combination with the BR-M445/M446 (calipers), BL-M445/T445
(brake lever), SM-RT53 / RT51 (rotor) and Shimano pad unit (B01S).
• Shimano disc brake systems are not compatible with tandem bicycles.
Because tandem bicycles have a high overall weight, the load on the brake system
increases during brake operation. If hydraulic disc brakes are used with tandem
bicycles, the oil temperature will become too high and vapor locks or ruptures in the
brake hoses may occur, and this will cause the brakes to fail.
• Obtain and read the service instructions carefully prior to installing the parts. Loose,
worn or damaged parts may cause the bicycle to fall over and serious injury may occur
as a result. We strongly recommend only using genuine Shimano replacement parts.
• Read these Technical Service Instructions carefully, and keep them in a safe place for
later reference.
< If brake operation is sluggish when the lever is depressed >
Set the brake lever so that it is parallel to the ground, and then gently depress the
brake lever several times and wait for the bubbles to return to the reservoir tank. It
is recommended that you then remove the reservoir tank cover and fill the reservoir
tank with mineral oil until no bubbles remain.
If the brakes still operate sluggishly, bleed the air from the brake system.
(Refer to "Adding the mineral oil and bleeding air".)
Vapor lock is a phenomenon in which the oil inside the brake system becomes
heated, which causes any water or air bubbles inside the brake system to expand.
This can then result in a sudden increase in the brake lever stroke.
CAUTION
■ Handling the mineral oil
• Use safety glasses when handling, and avoid contact with eyes. Contact with eyes may
result in irritation. In the event of eye contact, flush with fresh water and seek medical
assistance immediately.
• Use gloves when handling. Contact with skin may cause a rash and discomfort.
In the event of skin contact, wash well with soap and water.
Pad wear
indicators
• Inhalation of oil mist or vapors may cause nausea. Cover nose and mouth with
a respirator type mask and use in a well ventilated area. If mist or vapor is
inhaled, go immediately to an area with fresh air. Cover up with a blanket. Stay
warm and stable and seek professional medical advice.
• Do not drink. May cause vomiting or diarrhea.
• Keep out of reach of children.
• Do not cut, heat, weld or pressurize the oil container, as this may cause
explosion or fire.
• Disposal of Used Oil : Follow local county and/or state codes for disposal. Use
care when preparing oil for disposal.
• Directions : Keep the container sealed to prevent foreign objects and moisture
from getting inside, and store it in a cool, dark area away from
direct sunlight or heat.
■ Burn-in period
• Disc brakes have a burn-in period, and the braking force will gradually increase
as the burn-in period progresses. Make sure that you are aware of any such
increases in braking force when using the brakes during the burn-in period. The
same thing will happen when the brake pads or rotor are replaced.
■ When cleaning with a compressor
• If disassembling the caliper body to clean the internal parts using a
compressor, note that moisture from the compressed air may remain on the
caliper components. Let the caliper components dry sufficiently before
reassembling the calipers.
Note
• The SM-RT53L/M 203/180 mm rotors has a larger diameter and greater
curvature than the 160 mm cross-country rotors. As a result, it may touch the
brake pads.
• If the brake caliper mounting boss and the dropout are not parallel, the rotor
and caliper may touch.
• When the bicycle wheel has been removed, it is recommended that pad
spacers should be installed. The pad spacers will prevent the piston from
coming out if the brake lever is depressed while the wheel is removed.
• If the brake lever is depressed without the pad spacers installed, the pistons will
protrude further than is normal. Use a flat-tipped screwdriver or similar tool to
push back the brake pads, while being careful not to damage the surfaces of
the brake pads. (If the brake pads are not installed, push the pistons straight
back in, while being careful not to damage them.)
If it is difficult to push the brake or pistons back, remove the bleed screw and
install the oil funnel and then try again. You will need to carry out the bleeding
operation at this time too.
• Use isopropyl alcohol, soapy water or a dry cloth when carrying out cleaning
and maintenance of the brake system. Do not use commercially-available brake
cleansers or silencing agents, as they can cause damage to parts such as
seals.
• Do not remove the pistons when disassembling the calipers.
• If the rotor is worn, cracked or warped, it should be replaced.
• Parts are not guaranteed against natural wear or deterioration resulting from
normal use.
• For maximum performance we highly recommend Shimano lubricants and
maintenance products.
<SM-RT53 / 53M / 53L>
Tightening torque:
40 - 50 N·m {350 - 435 in. lbs.}
Rotor fixing lock ring
TL-LR15 / LR10
■ Installation of the calipers (BR-M445/M446) and securing the hose
For international-standard mounts, attach adapters to calipers for post-type mounts.
(Separate front and rear adapters are available.)
1. Loosen the caliper fixing bolts so that the caliper can move sideways, and then install the
adapter to the frame.
2. Depress the brake lever so that the rotor is being clamped by the pads, and then tighten the
caliper fixing bolts.
■ Installation of the hose
Refer to the Service Instructions for the SM-BH59 brake hose (SI-8H20) for details on installing
the hose.
Do not let the hose become twisted when installing. Make sure that the calipers and levers are in
the positions shown in the illustrations.
< For right lever >
< For left lever >
Provisionally install the caliper to the
frame (so that the caliper can move
sideways), depress the brake lever so that
the rotor is being clamped by the pads,
and then tighten the caliper fixing bolts.
Caliper fixing
bolts
Caliper fixing
bolts
● Post mounting type
Caliper
Rotor
Adapter
● International standard mounting type
Tightening torque:
6 - 8 N·m {53 - 69 in. lbs.}
< Front >
< Rear >
Tightening torque:
6 - 8 N·m {53 - 69 in. lbs.}
< Front >
Adapter fixing
bolts
Adapter fixing
bolts
Caps
< Front > < Rear >
Post type
Caps
Caps
Either a cap method or a wire ring method can be used to stop the bolts from turning.
Use whichever method is suitable for the front fork and frame.
160 mm rotor
Caps
Caps
< Front > < Rear >
Post type
Wire
Caps
203 / 180 mm rotors
<Wire ring method>
If bolt ➀ tries to loosen (turn in the counterclockwise direction), force is
applied via the wire to turn bolt ➁ in the tightening direction (clockwise).
However, bolt ➁ cannot turn any further in the tightening direction.
Accordingly, this prevents bolt ➀ from turning in the loosening direction
because it is also connected via the wire. If either one of the bolts tries to
loosen, this causes a force to be applied to the other bolt to turn it in the
tightening direction. In other words, this system prevents the bolts from
loosening.
Bolt ➀
Bolt ➁
This service instruction explains how to use and maintain the Shimano bicycle
parts which have been used on your new bicycle.
For any questions regarding your bicycle or other matters which are not
related to Shimano parts, please contact the place of purchase or the bicycle
manufacturer.
* Service Instructions in further languages are available at :
http://techdocs.shimano.com
Please note: specifications are subject to change for improvement without notice. (English)
© Jan. 2011 by Shimano Inc. XBC IZM Printed in Malaysia.
SI-8J50A-002-00
■ Wheel spoke lacing
Check that the spokes have been laced as shown in the illustration.
A radial assembly cannot be used.
Lace the spokes as shown in Figure 1 below for the left side of the front wheel
(the side where the roter is installed), and the left and right sides of the rear
wheel, and as shown in Figure 2 below for the right side of the front wheel.
Rotating
direction of
wheel
Fig. 1 Fig. 2
Front rightRear left Rear rightFront left
Installation
The following tools are needed to assemble this product.
Tool
TL-LR15 or TL-LR10
Allen key 5 mm
Allen key 5 mm
Radio pliers
8 mm wrench
Allen key 2 mm
Phillips screwdriver #2
Socket wrench 7 mm
Usage location
Rotor fixing lock ring
Brake lever fixing bolt
Caliper fixing bolt / Adapter fixing bolts
Brake pad fixing shaft
Brake hose fixing bolt
Bleed screw
Cable supporter
Bleed nipple
Oil funnel, Oil stopperBleeding
■ Installation of the rotor
<SM-RT51 / 51M>
Install the rotor and the rotor tightening
plate to the hub, and then install and
tighten the bolts as shown in Fig. 1.
While wearing gloves, apply a force to the rotor to
turn it in a clockwise direction as shown in Fig. 2.
While doing this, tighten the rotor fixing bolts in
the order shown in the illustration.
Use a flat-tipped screwdriver or similar tool to bend the edges of the tightening
plate over the heads of the bolts as shown in Fig. 3.
Fig. 1
Tightening plate
Rotor
Hub
Tightening torque:
2 - 4 N·m {18 - 35 in. lbs.}
Fig. 2 Fig. 3
Tightening plate
Rotor fixing bolts
(#T25 torx)
*
*
TORX is a registered
trademark of Camcar LLC.
Pad spacer
Maintenance
■ Brake pad replacement
If oil adheres to the brake pads after oil is added, or if the brake pads are worn down to a
thickness of 0.5 mm, replace the brake pads.
1. Remove the wheel from the frame,
and remove the brake pads as shown
in the illustration.
2. Clean the pistons and surrounding area.
5. Depress the brake lever several times to check that the operation becomes stiff.
6. Remove the pad spacers, install the wheel, and then check that there is no interference
between the rotor and the caliper. If they are touching, adjust while referring to
"Installation of the caliper".
3. Push the piston back in as far as it will
go, while being careful not to twist it.
Note:
This brake system is designed so that as the brake pads become worn,
the pistons gradually move outward to automatically adjust the clearance between
the rotor and the brake pads. Therefore, you need to push the pistons back to their
original positions when replacing the brake pads.
4. Install the new brake pads, and
then install the pad spacers.
Brake pads
Piston
■ Adjustment when the pistons are not operating correctly
The caliper mechanism includes two pistons. If these pistons do not operate properly or if
they protrude unevenly, or if the brake pads remain in contact with the rotor, adjust the
pistons by the following procedure.
1. Remove the wheel and the brake pads.
Clean the pistons and surrounding area.
2. Push the piston back in straight, without bending it.
3. Install the brake pads and the pad spacers.
4. Depress the brake lever as far as it will go, and then operate it several more times so
that the two pistons all move to their initial positions.
5. Remove the pad spacers, install the wheel, and then check that there is no interference
between the rotor and the caliper. If they are touching, adjust while referring to
"Installation of the caliper".
■ Mineral oil replacement period
It is recommended that you replace the oil inside the reservoir tank if it becomes
severely discolored. Use only genuine Shimano mineral oil.
Dispose of the waste oil according to proper country and/or state disposal
regulations.
If the oil level drops after the brake pads have been replaced or the piston has been
adjusted because it is not working correctly, the braking force may become weaker. If
this happens, install the oil funnel and carry out the bleeding operation to top up the oil.
Be sure to read the service instructions for the “Adding mineral oil
and bleeding air” in conjunction with these service instructions.
* An oil funnel and an oil stopper will be required when bleeding the
air.
Bleed screw
Oil funnel
Oil stopper
