Shimano Tiagra ST-R4020/BR-RS405 mech. shifting/hydr. front brake, left, Flat Mount, hose 1,000 mm

WARNING
Information on product installation, adjustment, and replacement not found in the user's manual can be obtained at the place of purchase or from a distributor. A dealer's manual intended for professional and experienced bicycle mechanics can be found on our website (https://si.shimano.com).
For safety, thoroughly read this “user's manual” before use, follow it for correct use, and store it for future reference.
The following instructions must always be followed to prevent personal injury and physical damage to equipment and surroundings. Instructions are classified according to the degree of danger or damage that may occur in case of incorrect product use.
DANGER - Failure to follow instructions will result in death or serious injury.
WARNING - Failure to follow instructions could result in death or serious injury.
CAUTION - Failure to follow instructions could result in personal injury or physical damage to equipment and surroundings.

WARNING
- Because each bicycle may handle slightly differently depending on the model, learn the correct braking technique (including brake lever pressure and bicycle handling characteristics) and operation of your bicycle. Improper use of the bicycle's braking system can result in loss of control, which can lead to serious injury due to a fall or collision.
- Do not disassemble or modify the product. This may cause the product to malfunction, you may fall unexpectedly and be seriously injured.
- This hydraulic brake system has different braking characteristics than rim brake type braking characteristics, indicating a relatively large braking force at the beginning of braking (higher than rim brake type); familiarize yourself sufficiently with the braking characteristics before use. If you ride the bicycle without thoroughly familiarizing yourself with the braking characteristics, braking may result in a fall from the bicycle with possible serious injury or fatal accident.
- The braking force of the hydraulic brake system will increase with the size of the disc brake rotor (140 mm, 160 mm, 180 mm, 203 mm).
- Do not use a 203 mm disc brake rotor. This will excessively increase the braking force, which can cause loss of control of the bicycle, a fall, and serious injury.
- Use a 180 mm disc brake rotor only if you cannot obtain sufficient braking force with a 160 mm disc brake rotor during a test ride, for example, when riding an electrically assisted road bicycle or if the rider is heavy. Otherwise, you may lose control of the bicycle, fall, and be seriously injured.
- If the braking force seems too great or too small, stop using it and consult the place of purchase or a distributor. Accidents or falls may occur due to loss of control of the bicycle, which can result in serious injury.
- Keep your fingers away from the rotating disc brake rotors. The disc brake rotor is sharp enough to cause serious finger injury if fingers get caught in the holes of the moving rotor.
- Do not touch the calipers or disc brake rotor while riding or immediately after dismounting the bicycle. During braking, the calipers and disc brake rotor become hot, so touching them can cause burns.
- Do not allow oil or grease to get on the disc brake rotor and brake pads. Riding the bicycle with oil or grease on the disc brake rotor and brake pads can cause the brakes to malfunction and lead to serious injury due to a fall or collision.
- Check the thickness of the brake pads and do not use them if they are 0.5 mm or less thick. Otherwise, this may cause the brakes to malfunction and lead to serious injury due to a fall or collision.
- Do not use the disc brake rotor if it is cracked or deformed. The disc brake rotor may break and lead to serious injury due to a fall.
- Do not use the disc brake rotor if its thickness is 1.5 mm or less. Also, do not use it if the aluminum surface is visible. The disc brake rotor may break and lead to serious injury due to a fall.
- Do not apply the brakes continuously. This can cause a sudden increase in brake lever engagement, cause the brakes to malfunction, and lead to serious injury due to a fall or collision.
- Do not use the brakes if fluid is leaking. This can cause the brakes to malfunction and lead to serious injury due to a fall or collision.
- Do not apply the front brake too strongly. If you do, the front wheel may lock up and the bicycle may flip forward, causing serious injury.
- Because the required braking distance will be longer during wet weather, reduce your speed. Apply the brakes early and gently. You may fall or crash and be seriously injured.
- Wet road surfaces can cause tires to lose traction. To prevent this, reduce your speed and apply the brakes early and gently. If the tires lose traction, you may fall and be seriously injured.

CAUTION
- Warnings regarding genuine SHIMANO mineral oil
- In case of eye contact, rinse the eye with clean water and seek immediate medical attention. Eye contact can cause irritation.
- In case of skin contact, wash thoroughly with soap and water. Skin contact can cause rashes and discomfort.
- Protect your nose and mouth with a protective respiratory mask and use in a well-ventilated area. Inhalation of mineral oil vapor or fumes can cause nausea.
- After inhaling mineral oil vapor or fumes, immediately go to a place with fresh air. Cover yourself with a blanket. Stay warm in a stable position and seek professional medical attention.
- Break-in period
-Disc brakes have a certain break-in period, and the braking force gradually increases with the increasing break-in period. Accidents or falls may occur due to loss of control of the bicycle, which can result in serious injury. The same situation will occur if the brake pads or disc brake rotor are replaced.