描述
# SHIMANO SM-BB91-42A 五通（壓入式 / 無內套管）
**XTR 級壓入式五通，專為 Specialized OSBB 車架而設。**
SHIMANO SM-BB91-42A 屬 XTR 系列壓入式五通，採用纖維增強聚合物軸承杯，有效降低車架異響及損壞風險。密封式軸承設計，防塵防水，免維護。此版本**不包含內套管**，適合原廠已配備內套管或無需內套管的車架。
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## 為何選擇 SM-BB91-42A？
– **XTR 系列品質**：頂級傳動系統工藝，踩踏順暢高效
– **纖維增強聚合物軸承杯**：降低車架異響及損壞風險
– **密封式軸承**：防塵防水，免維護
– **壓入式安裝**：簡易安裝，穩固可靠
– **兼容 Specialized OSBB 車架**：專為 84.5mm 五通殼寬度設計
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## 適合哪些車架？
配備 **Specialized OSBB 壓入式五通標準**的登山車車架（五通殼直徑 42mm，寬度 84.5mm）。
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## 技術規格
| 項目 | 規格 |
|—|—|
| 型號 | SM-BB91-42A |
| 系列 | XTR |
| 五通標準 | 壓入式（Press-Fit） |
| 五通殼直徑 | 42mm |
| 五通殼寬度 | 84.5mm |
| 軸心直徑 | 24mm（Hollowtech II） |
| 軸承類型 | 密封式鋼軸承 |
| 軸承杯材質 | 纖維增強聚合物 |
| 重量 | 約 72g |
| 產地 | 日本 |
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## 兼容性
– **曲柄**：SHIMANO Hollowtech II 登山車曲柄（24mm 軸心），包括 XTR、XT、SLX 等 MTB 型號
– **車架**：Specialized OSBB 壓入式五通殼（42mm 直徑，84.5mm 寬度）
– **相容寬度**：可透過墊片兼容 89.5mm（使用 2.5mm 墊片）及 92mm（使用兩個墊片，墊片需另購）
– **安裝工具**：TL-BB12 壓入式五通工具
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## 備註
– **此版本不包含內套管**（Inner Sleeve）。若車架五通殼內部有開口，需另行選購內套管。
– 隨附 2.5mm 墊片。
– 安裝需使用壓入工具，建議由合資格技師安裝。
– 此為壓入式五通，不適用於 BSA 螺紋式車架。
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# SHIMANO SM-BB91-42A BOTTOM BRACKET (Press-Fit Type) – Without Packing
**XTR-Grade Press-Fit Bottom Bracket for Specialized OSBB Frames.**
The SHIMANO SM-BB91-42A is an XTR-level press-fit bottom bracket featuring fibre-reinforced polymer cups that reduce the risk of frame noise and damage. Sealed bearings keep out dirt and water, maintenance-free. This version **does not include the inner sleeve**, suitable for frames already equipped with an inner sleeve or those that do not require one.
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## Why SM-BB91-42A?
– **XTR Series Quality**: Top-tier drivetrain craftsmanship for smooth, efficient pedalling
– **Fibre-Reinforced Polymer Cups**: Reduce the risk of frame noise and damage
– **Sealed Bearings**: Dirt and water protection, maintenance-free
– **Press-Fit Installation**: Easy installation, secure and reliable
– **Compatible with Specialized OSBB Frames**: Specifically designed for 84.5mm shell width
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## Ideal For
Mountain bike frames with the **Specialized OSBB press-fit bottom bracket standard** (42mm shell diameter, 84.5mm shell width).
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## Technical Specifications
| Item | Specification |
|—|—|
| Model | SM-BB91-42A |
| Series | XTR |
| BB Standard | Press-Fit |
| Shell Diameter | 42mm |
| Shell Width | 84.5mm |
| Axle Diameter | 24mm (Hollowtech II) |
| Bearing Type | Sealed Steel Bearings |
| Cup Material | Fibre-Reinforced Polymer |
| Weight | Approx. 72g |
| Origin | Japan |
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## Compatibility
– **Cranks**: SHIMANO Hollowtech II MTB cranks (24mm axle), including XTR, XT, SLX and other MTB models
– **Frames**: Specialized OSBB press-fit shells (42mm diameter, 84.5mm width)
– **Compatible Widths**: Can fit 89.5mm (with 2.5mm spacer) and 92mm (with two spacers, sold separately)
– **Installation Tool**: TL-BB12 press-fit bottom bracket tool
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## Notes
– **This version does not include the inner sleeve**. If the frame has openings inside the bottom bracket shell, an inner sleeve must be purchased separately.
– Includes 2.5mm spacer.
– Professional installation recommended; requires a press tool.
– This is a press-fit bottom bracket, not suitable for BSA threaded frames.
