The Shimano Tourney RD-TY300 is an entry-level, highly popular rear derailleur optimized for 6-speed and 7-speed drivetrains. It features a sleek black finish, a long cage (SGS) design, and a standard direct attachment bolt. It is a reliable choice for casual mountain bikes, commuter hybrids, and kids' bikes.

Technical Specifications Quick-View

Feature Breakdown

• Direct Attachment:
  This model mounts via a standard M10 bolt directly into a dedicated rear derailleur hanger on your bike frame.
  Note: This is not the "hub axle/claw" mount version.
• SGS Long Cage:
  The extended cage yields a 43-tooth total capacity, giving it enough room to take up chain slack on bikes running a 3x6 or 3x7 triple-crank setup.
• Double Servo Design:
  This technology keeps the derailleur pulley moving in a precise path close to the cassette cogs, ensuring smooth, accurate, and predictable shifting.
• SIS Index Shifting:
  Fully compatible with Shimano Index Shifting (SIS) systems, ensuring a crisp click-into-gear feel when paired with Shimano RevoShift (twist) or Tourney trigger shifters.
• B-Tension Adjustment Screw:
  Includes an adjustable B-tension screw, allowing you to fine-tune the gap between the upper guide pulley and the cassette cogs for optimal shifting performance.

Key Difference: RD-TY300 vs RD-TX800

If you are comparing this to the RD-TX800, here are the main differences:

• Speeds:
  The TY300 is strictly optimized for 6/7-speed chains and spacing, whereas the TX800 handles up to 8-speed systems.
• Pulleys:
  The TY300 uses standard 11-tooth pulleys, while the TX800 uses larger, smoother 13-tooth pulleys.
• Build:
  The TX800 has a slightly higher-grade finish and metal links, making it more durable under heavier use.

Are you looking to replace an old TY300 derailleur, or are you deciding between this and the TX800 for a budget build? Let me know your rear cassette/freewheel size (e.g., 14-28T or 11-34T MegaRange) so I can ensure it fits perfectly!