Product Description
Shimano 10J7A Idle Gear (A) (BNT1300) | Calcutta & Bantam Replacement
The Shimano 10J7A Idle Gear (A) (BNT1300) is a precision-molded internal drive component critical for the proper operation of your reel's level wind system. This gear acts as a primary link in the transmission chain, transferring rotational energy from the main drive gear to the worm shaft assembly. By ensuring perfect synchronization, it allows your line guide to travel smoothly across the spool, resulting in a flawless line lay and improved casting distance.
As a "sacrificial" polymer part, the 10J7A is designed to strip its teeth in the event of a mechanical jam (such as a line tangle or debris in the level wind), protecting the more expensive metal drive components from permanent damage.
Product Specifications
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Part Name: Idle Gear (A)
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Shimano Part Number: 10J7A
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Alternate Part Number: BNT1300
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Material: High-Tensile Industrial Nylon
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Placement: Intermediate drive train (Internal)
Compatible Reel Models
The BNT1300/10J7A is a staple component in many of Shimano’s legendary round baitcasting and conventional reels. It is a direct fit for the following series:
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Shimano Calcutta: CT200, CT201, CT251, CT251B, CT200GTB.
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Shimano Bantam: BKM200, BKM201, BKM2000, BKM201FS.
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Shimano Calcutta A/B/GTB: Fits various production years including '93, '95, '96, and '99 models.
Technical Note: In many Calcutta assemblies, it is highly recommended to replace Idle Gear (B) (BNT1301) at the same time to ensure even wear and perfect gear meshing. You can verify the exact layout for your specific year of manufacture by downloading the PDF schematics at www.reelschematic.com.
Maintenance & Lubrication Recommendation
Because this is a polymer gear interfacing with metal or other nylon components, choosing the right lubricant is vital to prevent the material from becoming brittle or wearing prematurely. We recommend Deuthlon Lubricants:
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For Gear Teeth: Apply Deuthlon Reel Gear Grease. Its high-tack formula is specifically designed to stay on the gear teeth even during high-speed retrieves, providing a quiet mesh and a superior moisture barrier.
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For the Gear Post: Use a drop of Deuthlon Power Cast Oil on the internal shaft or post where the gear sits. This ensures the gear spins with zero resistance, reducing the torque required to turn the handle.
Why Use Genuine Shimano 10J7A Parts?
Using the original BNT1300 ensures your reel maintains its factory-specified timing and safety features:
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Precision Timing: The exact tooth count and pitch prevent the line guide from "stalling" at the ends of the spool.
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Component Protection: The material density is calibrated to fail safely during a jam, saving your main gear.
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Saltwater Resilience: Engineered to resist the chemical breakdown often caused by harsh saltwater environments and cleaning agents.
