Product Description
Shimano 10EX8 Ball Bearing (BNT3927, TGT1652 & RD17751)
The Shimano 10EX8 Ball Bearing is one of the most versatile and high-performance precision bearings in the Shimano catalog. Known by various regional and series-specific codes—BNT3927 for baitcasters, TGT1652 for offshore reels, and RD17751 for spinning reels—this bearing is a "workhorse" component.
In baitcasting reels, it is most commonly found supporting the Drive Shaft (crank shaft) or the Pinion Gear. In spinning reels, it is frequently used as a Rotor Nut Bearing or a high-load Drive Gear Bearing. Because it is situated in high-torque areas of the reel, it is shielded to protect against contaminants while providing the smooth, frictionless rotation that Shimano is famous for.
Product Specifications
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Part Name: Ball Bearing
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Part Number: 10EX8
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Shimano Codes: BNT3927 / TGT1652 / RD17751
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Type: Shielded Stainless Steel (Anti-Rust Bearing / ARB)
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Function: Supports rotating shafts and gears to reduce friction and mechanical wear.
Alternate Part Numbers
This part is a cross-category standard and appears in schematics as:
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BNT3927 (Standard Baitcasting)
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TGT1652 (Conventional/Saltwater)
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RD17751 (Modern Spinning)
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RD13268 (Older Spinning series)
Compatibility & Fitment
The 10EX8 is utilized across nearly the entire Shimano lineup. It is a direct factory fit for the following series:
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Shimano Stradic Series: ST-2500HGFL, 4000FL, C5000XGFL (and Ci4+ models)
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Shimano Curado Series: CU-200E, 200G, 200K, 300K, and MGL versions
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Shimano Stella Series: Fits select 2500 and 4000 size internals (Verify via RD code)
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Shimano Talica Series: TAC-12, 16, 20, 25 (Internal shaft support)
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Shimano Saragosa SW: Fits various drive train and line roller assemblies
Key Features
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A-RB / S-A-RB Technology: Depending on the specific year of manufacture, these are often "Anti-Rust Bearings," featuring at least 10 times the corrosion resistance of standard stainless steel.
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Precision Tolerance: Machined to exact ABEC standards to ensure zero "play" or wobble in the handle or gear mesh.
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Shielded Protection: Equipped with dual shields to keep factory grease in and destructive salt, sand, and water out.
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Direct OEM Fit: Guaranteed to match the exact millimeter dimensions required for the drive shaft or pinion housing of your specific reel.
Maintenance & Troubleshooting
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Symptom of Failure: If your reel makes a "whirring" sound when you turn the handle, or if the handle feels "gritty" under load, this bearing is likely the culprit.
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The "Spin Test": Remove the bearing and spin it on the tip of a pencil. If you feel any vibration or hear noise, it has internal pitting and should be replaced.
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Lubrication: For drive shaft or gear support, use a high-quality reels grease (like Shimano DG06). For high-speed applications like spool support, use a light oil (like Shimano Bantam Oil).
Pro Tip: Never use WD-40 or automotive degreasers on these bearings, as they can strip the internal protective coatings. For the exact location of the 10EX8 in your reel's drive train, refer to the PDF schematics at www.reelschematic.com.
