Inngangur
The microSHIFT M21 Rear Derailleur is engineered for reliable and smooth shifting performance on bicycles equipped with 6- or 7-speed Shimano road and mountain shifter systems. Its robust composite and steel construction ensures durability, making it an ideal component for restoring or upgrading a wide range of bicycles. This derailleur features a long cage design, suitable for double or triple chainring setups with up to a 32T cassette, and includes a frame hanger attachment for straightforward installation.
Vara lokiðview

Mynd 1: Framan view of the microSHIFT M21 Rear Derailleur, showcasing its compact design and mounting points.

Mynd 2: Hlið view of the microSHIFT M21 Rear Derailleur, highlighting the long cage and pulley wheels.
Helstu eiginleikar:
- Samhæfni: Designed for 6- and 7-speed Shimano road and mountain shifter systems.
- Framkvæmdir: Durable composite and steel components for long-lasting performance.
- Cage Type: Long cage, suitable for wide-range gearing, including double or triple chainring setups.
- Cassette Capacity: Supports cassettes up to 32 teeth.
- Uppsetning: Includes a frame hanger attachment for direct mounting.
Uppsetning og uppsetning
Proper installation is crucial for optimal performance and safety. If you are unsure about any step, consult a professional bicycle mechanic.
Verkfæri sem þarf:
- Hex key set (typically 5mm)
- Cable cutters
- Feiti
- Tog skiptilykill (ráðlagt)
Uppsetningarskref:
- Remove Old Derailleur (if applicable): Shift the chain to the smallest cog. Loosen the cable anchor bolt and remove the shift cable. Unscrew the derailleur mounting bolt from the frame hanger and remove the old derailleur.
- Prepare Frame Hanger: Ensure the frame hanger is clean and free of debris. Apply a thin layer of grease to the threads of the derailleur mounting bolt.
- Mount New Derailleur: Align the microSHIFT M21 derailleur with the frame hanger. Insert the mounting bolt through the derailleur and thread it into the frame hanger. Tighten the bolt securely, referring to your bicycle's frame manufacturer specifications for torque values if available. Do not overtighten.
- Setja upp keðju: Route the bicycle chain through the derailleur's cage, ensuring it passes correctly over the guide pulley and tension pulley.
- Attach Shift Cable: Route the shift cable through the cable housing and into the derailleur's cable routing channel. Secure the cable under the cable anchor bolt, ensuring there is no slack. Tighten the cable anchor bolt.
- Upphafleg aðlögun: Perform initial limit screw adjustments (High and Low) and B-tension adjustment to ensure the derailleur aligns correctly with the cassette cogs. Refer to the "Operating Instructions" section for detailed adjustment procedures.
Notkunarleiðbeiningar
Once installed, the microSHIFT M21 Rear Derailleur requires proper adjustment for smooth and precise shifting. These adjustments should be performed with the bicycle securely mounted in a repair stand.
Limit Screw Adjustment:
Limit screws prevent the derailleur from shifting the chain off the smallest (High) or largest (Low) cog.
- High Limit (H) Screw: Shift the chain to the smallest cog on the cassette. Turn the 'H' screw clockwise until the guide pulley is directly aligned with the center of the smallest cog. Turn it counter-clockwise slightly if the chain rubs or cannot reach the smallest cog.
- Low Limit (L) Screw: Shift the chain to the largest cog on the cassette. Turn the 'L' screw clockwise until the guide pulley is directly aligned with the center of the largest cog. Turn it counter-clockwise slightly if the chain rubs or cannot reach the largest cog.
B-Tension Adjustment:
The B-tension screw adjusts the gap between the guide pulley and the cassette cogs.
- Shift the chain to the largest cog on the cassette and the smallest chainring on the crankset.
- Turn the B-tension screw (located on the derailleur body, facing the rear of the bike) clockwise to increase the gap, or counter-clockwise to decrease it.
- Adjust until the guide pulley clears the largest cog by approximately 5-6mm. This prevents the pulley from rubbing on the cogs and ensures smooth shifting across the entire cassette.
Cable Tension Adjustment:
Fine-tune shifting performance using the barrel adjuster on the shifter or derailleur.
- If shifting from a smaller cog to a larger cog is slow or hesitant, turn the barrel adjuster counter-clockwise (out) to increase cable tension.
- If shifting from a larger cog to a smaller cog is slow or hesitant, turn the barrel adjuster clockwise (in) to decrease cable tension.
Viðhald
Regular maintenance extends the life of your derailleur and ensures consistent performance.
- Þrif: Periodically clean the derailleur, especially the pulley wheels, to remove dirt, grime, and old lubricant. Use a degreaser and a brush.
- Smurning: After cleaning, apply a small amount of bicycle-specific lubricant to the pivot points of the derailleur and the pulley wheel bearings. Avoid over-lubricating, as this can attract more dirt.
- Skoðun: Regularly inspect the derailleur for any signs of damage, bending, or excessive wear on the pulley wheels. Check that all bolts are securely tightened.
- Cable and Housing: Inspect the shift cable and housing for fraying, kinks, or corrosion. Replace them if necessary, as damaged cables can significantly impair shifting performance.
Úrræðaleit
Algeng vandamál og mögulegar lausnir á þeim.
| Vandamál | Möguleg orsök | Lausn |
|---|---|---|
| Slow or hesitant upshifts (to larger cog) | Insufficient cable tension, dirty cable/housing | Increase cable tension with barrel adjuster (counter-clockwise). Clean or replace cable/housing. |
| Slow or hesitant downshifts (to smaller cog) | Excessive cable tension, dirty cable/housing | Decrease cable tension with barrel adjuster (clockwise). Clean or replace cable/housing. |
| Chain rubs on derailleur cage or jumps off cogs | Incorrect limit screw adjustment, bent derailleur hanger | Adjust H or L limit screws. Inspect and straighten/replace derailleur hanger. |
| Noisy shifting or chain skipping | Incorrect B-tension, worn chain/cassette/pulley wheels | Adjust B-tension screw. Inspect and replace worn drivetrain components. |
Tæknilýsing
| Eiginleiki | Smáatriði |
|---|---|
| Gerðarnúmer | RD-M21LA |
| Vörumerki | microSHIFT |
| Samhæfni | 6-speed, 7-speed Shimano road and mountain systems |
| Cage Length | Long Cage |
| Max Cog Size | 32T (for double or triple setup) |
| Gerð uppsetningar | Frame Hanger (Direct Mount) |
| Efni | Composite and Steel |
| Þyngd hlutar | 12.8 aura (u.þ.b. 363 grömm) |
Ábyrgð og stuðningur
microSHIFT products are manufactured to high standards and are designed for durability and performance. For specific warranty information regarding your M21 Rear Derailleur, please refer to the warranty policy provided at the point of purchase or visit the official microSHIFT webGeymið kaupkvittunina ef þið viljið gera kröfur um ábyrgð.
For technical support, installation assistance, or troubleshooting beyond this manual, please contact microSHIFT customer service or consult with an authorized microSHIFT dealer.





