Product Description
Shimano 10J77 Idle Gear A (BNT3217) | Chronarch & Antares Replacement
The Shimano 10J77 Idle Gear A is a high-precision internal transmission component designed to synchronize the level wind system with the spool's rotation. This specific gear serves as a vital link in the drive train, ensuring that the line guide moves laterally with perfect timing to provide a smooth and even line lay on the spool.
Constructed from durable, low-friction polymer, this idle gear is engineered to provide quiet operation and consistent performance under load. As a common wear item in high-use baitcasting reels, replacing a worn or stripped 10J77 is essential for restoring factory-spec line management and preventing backlashes caused by uneven line stacking.
Product Specifications
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Part Name: Idle Gear A
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Primary Part Number: 10J77
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Alternate Part Number: BNT3217
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Material: Reinforced Industrial Polymer
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Component Type: Level Wind Drive Gear
Compatible Reel Models
The 10J77 is a versatile part used in several of Shimano's flagship low-profile baitcasting reels. It is a direct fit for the following models:
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Shimano Chronarch 100B Series: CH100B, CH100BPV, CH100BSV, CH101B, CH101BPV, CH101BSV.
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Shimano Calais DC: CL200DC, CL201DC (Digital Control models).
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Shimano Antares: ANT100, ANT100HG, ANT101, ANT101HG.
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Shimano 05CH100B: Specific 2005 production year models.
Service Tip: To ensure this part is correctly oriented within your specific reel's frame, refer to the official PDF schematics available at www.reelschematic.com.
Maintenance & Lubrication Recommendation
Because the Idle Gear A interfaces directly with other drive components, using the correct lubricant is critical to prevent premature wear and maintain a silent retrieve. We recommend Deuthlon Lubricants:
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For Gear Teeth: Apply a light coating of Deuthlon Reel Gear Grease. Its high-tack formula is designed to stay on the plastic teeth, providing a protective barrier that resists water and prevents the polymer from becoming brittle.
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For the Gear Post/Shaft: Use a single drop of Deuthlon Power Cast Oil on the post before sliding the gear into place. This ensures the gear spins with minimal resistance, improving the overall smoothness of the reel.
Why Use Genuine Shimano 10J77?
The 10J77 (BNT3217) is manufactured to the exact tolerances required for Shimano's high-speed gear ratios. Using a genuine OEM replacement ensures:
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Perfect Pitch: Prevents gear "chatter" and ensures the level wind moves at the intended speed.
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Sacrificial Protection: Designed to fail before your expensive main or pinion gears if the level wind becomes jammed.
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Corrosion Resistance: The polymer material is impervious to saltwater, making it ideal for both fresh and inshore applications.
