The bottom bracket shell Shimano XTR SM-BB93 Hollowtech II is designed for mountain bikes fitted with a frame featuring a bottom bracket threaded to the 68 mm or 73 mm BSA standard. It is designed for cyclists Shimano compatible Hollowtech II with a 24 mm spindle and features the XTR design, which is engineered to deliver smooth rotation, a good seal and excellent durability for off-road use.
With its external races and protected bearings, the Shimano XTR SM-BB93 provides a reliable solution for replacing a worn bottom bracket and restoring smooth drivetrain operation.
An XTR bottom bracket designed for mountain biking
The SM-BB93 is part of the range Shimano XTR, designed for demanding mountain biking. Shimano highlights, in particular, its smooth rotation as well as its improved waterproofing performance to withstand the stresses associated with off-road use.
The casing complies with the standard Hollowtech II, with a 24 mm bottom bracket spindle. It fits frames with a threaded bottom bracket shell BSA 68 or 73 mm.
This external bearing design allows the bearings to be positioned outside the bottom bracket shell and contributes to the rigidity and efficiency of the Hollowtech II system.
Excellent waterproofing for mountain biking
Mountain biking exposes the bottom bracket to water, mud, dust and splashes in particular. The SM-BB93 features seals designed to improve the protection of the bearings and their long-term durability.
Shimano indicates that this case is robust enough for use on mountain bikes and highlights its high-precision waterproofing system.
This design ensures that rotation remains smooth and minimises the ingress of contaminants into the bearings.
Hollowtech II compatibility
The Shimano XTR SM-BB93 is intended for cyclists Shimano fitted with the system Hollowtech II with a 24 mm spindle.
In particular, it is compatible with several generations of XTR cranksets, including:
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XTR FC-M980
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XTR FC-M985
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XTR FC-M9000
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XTR FC-M9020
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XTR FC-M9100
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XTR FC-M9120
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XTR FC-M9125
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XTR FC-M9130
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Shimano FC-MT900
However, exact compatibility must be checked depending on the crankset and the frame configuration.
BSA standard 68 / 73 mm
The SM-BB93 is a model threaded and not a Press-Fit housing.
It is compatible with frames that have:
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Standard: BSA / BSC
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Box width: 68 or 73 mm
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Compatible shaft diameter: 24 mm
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Technology: Shimano Hollowtech II
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Editing: external screw-in bowls
The internal diameter specified for the BSA standard is approximately 34.8 mm.
Assembly of the Shimano XTR SM-BB93
The SM-BB93 fits directly into a BSA-threaded bottom bracket shell. The two cups are fitted on either side of the frame and accommodate the Hollowtech II bottom bracket axle.
The case comes with spacers allowing the assembly to be adapted to the configuration of the pedal set and the width of the gearbox. The documentation Shimano specifies, in particular, the spacer configurations to be used depending on the width of the box and the type of mounting.
To ensure correct assembly, it is recommended that you use the tool Shimano or a tool compatible with Hollowtech II cups, and to adhere to the tightening torques recommended by Shimano.
Why choose this case? Shimano XTR SM-BB93 ?
The Shimano XTR SM-BB93 combines Hollowtech II technology with a design specifically tailored to the demands of mountain biking. Its BSA threaded mount allows it to be fitted to frames with a 68 mm or 73 mm bottom bracket shell, whilst its external bearings are designed to provide smooth rotation and good resistance to off-road conditions.
This is a solution that is particularly well-suited for replacing an XTR bottom bracket or refurbishing a crankset Shimano Compatible with Hollowtech II.
Technical specifications
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Brand: Shimano
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Range: XTR
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Model: SM-BB93
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Manufacturer’s reference: ISMBB93B
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Type: MTB bottom bracket
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Technology: Hollowtech II
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Type of installation: threaded
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Standard: BSA / BSC
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Box width: 68 / 73 mm
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Compatible shaft diameter: 24 mm
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Bearing type: external bearings
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Cuvette material: aluminium
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Colour: black
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Stated weight: approximately 73 g
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Usage: Mountain biking
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Subject: Cross-Country, All-Mountain, Trail, Enduro
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Reference Shimano : SM-BB93 / ISMBB93B
(Translated review)
