1. はじめに
This instruction manual provides essential information for the proper installation, operation, and maintenance of your SHIMANO BB-UN300 Square Taper Bottom Bracket. Adhering to these guidelines will ensure optimal performance and longevity of the component. Please read this manual thoroughly before attempting any installation or maintenance procedures.
2.製品オーバーview
The SHIMANO BB-UN300 is a sealed cartridge bottom bracket designed for bicycles utilizing JIS square-taper cranksets. It features a durable construction with a hollow spindle for reduced weight and enhanced stiffness, contributing to efficient power transfer. The sealed design protects internal bearings from dirt and moisture, ensuring consistent performance across various riding conditions.
詳細な view of the SHIMANO BB-UN300 square taper bottom bracket, showing its sealed cartridge design, threaded cups, and square spindle ends. Markings for 'SHIMANO BB-UN300', 'VIA INDONESIA', '68', 'BC1.37 x 24', and 'LL123' are visible on the central body.
3. 仕様
| 仕様 | 詳細 |
|---|---|
| モデル番号 | BB-UN300 |
| スピンドルタイプ | JISスクエアテーパ |
| Shell Width Compatibility | BSA 68mm |
| スピンドルの長さ | 122.5mm (LL123) |
| インターフェイスの互換性 | English Thread (BC1.37 x 24) |
| 材料 | Steel Bearings, Steel Spindle |
| チェーンライン | 50mm |
4. インストール（セットアップ）
Proper installation is crucial for the performance and safety of your bottom bracket. If you are unsure about any steps, it is recommended to seek assistance from a qualified bicycle mechanic.
- Prepare the Bottom Bracket Shell: Ensure the bicycle's bottom bracket shell threads are clean, free of debris, and properly faced. Apply a thin layer of bicycle-specific grease to the threads of the bottom bracket shell.
- Install the Right-Hand Cup: The right-hand cup (drive side) typically has a standard right-hand thread (tightens clockwise). Carefully thread the right-hand cup into the bottom bracket shell by hand to avoid cross-threading. Once hand-tight, use a compatible bottom bracket tool to tighten it to the manufacturer's specified torque.
- Install the Left-Hand Cup: The left-hand cup (non-drive side) typically has a left-hand thread (tightens counter-clockwise). Carefully thread the left-hand cup into the bottom bracket shell by hand. Use a compatible bottom bracket tool to tighten it to the manufacturer's specified torque.
- クランクセットの取り付け: Slide your JIS square-taper crank arms onto the square spindle ends. Ensure they are fully seated.
- クランクアームを固定する: Install the crankarm fixing bolts (sold separately) and tighten them to the crankset manufacturer's specified torque.
重要： Always refer to the torque specifications provided by your crankset and bottom bracket manufacturers. Over-tightening or under-tightening can lead to component damage or unsafe operation.
5. 操作
Once correctly installed, the SHIMANO BB-UN300 bottom bracket provides a smooth and efficient interface for your bicycle's drivetrain. You should experience consistent pedaling without excessive friction or play. The sealed cartridge design means the internal bearings are protected and require minimal attention during normal operation.
- 初期チェック: After installation, perform a short test ride to ensure all components are functioning correctly and securely. Listen for any unusual noises.
- 定期点検: Periodically check for any looseness in the crank arms or bottom bracket.
6. メンテナンス
The SHIMANO BB-UN300 is designed for low maintenance due to its sealed cartridge construction. However, regular external cleaning and periodic checks are recommended to ensure optimal performance and extend its lifespan.
- クリーニング： Keep the exterior of the bottom bracket and surrounding areas clean from dirt, mud, and grime. Use a damp cloth and mild detergent if necessary. Avoid high-pressure washing directly at the seals.
- 再生の確認: Periodically check for any lateral or rotational play in the crank arms. If play is detected, first ensure the crankarm fixing bolts are tightened to specification. If play persists, the bottom bracket may require replacement.
- ノイズに耳を傾ける: Pay attention to any creaking or grinding noises during pedaling. These can indicate insufficient torque, contamination, or wear.
- ベアリングサービス: The sealed bearings of the BB-UN300 are not designed for user-level service or regreasing. If the bearings feel rough or exhibit significant play, the entire bottom bracket unit should be replaced.
7。 トラブルシューティング
Addressing common issues can help maintain your bottom bracket's performance.
- きしみ音:
- Ensure bottom bracket cups are tightened to the correct torque.
- Verify crankarm fixing bolts are tightened to the correct torque.
- Check for clean threads on both the bottom bracket and the frame shell. Re-grease and re-install if necessary.
- Excessive Play in Crank Arms:
- Confirm crankarm fixing bolts are securely tightened.
- If play persists after checking bolts, the bottom bracket bearings may be worn and require replacement of the unit.
- Difficulty Threading During Installation:
- Ensure the bottom bracket cup is perfectly aligned with the frame's bottom bracket shell threads before turning.
- Never force the threads. If resistance is met, unscrew, clean threads, and re-attempt alignment. Cross-threading can permanently damage the frame or bottom bracket.
- Ensure the correct thread direction for each cup (right-hand cup tightens clockwise, left-hand cup tightens counter-clockwise).
8. 保証とサポート
For warranty information, technical support, or replacement parts, please contact SHIMANO customer service or visit the official SHIMANO webサイトでご確認ください。保証請求に備えて購入証明書を保管してください。
