Shimano square taper bottom bracket BB-UN300, superb value for money for BSA bottom bracket.
This bottom bracket will give you value for money in good senses – durable and trusted for rugged operations from India to the US; bike makers love this for the price and durability. Shimano launched the BB-UN300 square taper bottom bracket as the successor of the BB-UN26 and BB-UN55. It covers various applications, from Touring and City bikes to older Road and Mountain bikes. BB-UN300 is available with BSA thread and in different axle lengths. In this type, the bottom bracket axle and crank are connected by a square taper, and the delivery does not include crank bolts.
BB-UN300
SHIMANO – Square Type Bottom Bracket – MTB – Standard Structure
Square Type Bottom Bracket
- SHIMANO quality/performance cartridge bearing square bottom bracket
- Better chain line stability with chain line stabilizer
- 3 structures available
- Standard, E-type, chaincase options
- Adapter Material: Aluminum
Specifications:
- Application: City, Touring, Road, All Mountain, Cross Country
- Type: BSA
- Shell Width: 68 mm
- Axle Length: 110 mm, 113 mm, 117.5 mm, 122.5 mm
- Axle Type: square taper (JIS)
- E-Type Compatibility: some models (Denoted by “E” in the model name)
- Chaincase Compatibility: some models (Denoted by “K” in the model name)
Technical Information:
- Bearings: Steel
- Axle Material: Steel
- Bottom Bracket Cup Material: aluminum (left), aluminum/steel (right)
Compatibility:
- For all cranks with JIS square mount
- FC-M311, FC-M315, FC-M351, FC-M361, FC-M371, FC-M430
- FC-M2000, FC-M3000
- FC-T3010
- FC-MT100
- FC-RS200
- FC-TY301, FC-TY501, FC-TY701
- FC-TX801
- FC-A070, FC-A073
Product Specifications
- MODEL NO: BB-UN300
- SERIES: TOURNEY TX800 Series
- Remarks: * w/ Crank arm fixing bolts spec. Only ** w/ Crank arm fixing bolts spec. is available
- Structure_Standard: ✔
- Axle length/shell width (mm)_107_68 (BC1.37): ✔
- Axle length/shell width (mm)_LL113_73 (BC1.37): ✔
- Axle length/shell width (mm)_D-H_68 (BC1.37): X *
- Axle length/shell width (mm)_117.5_68 (BC1.37): X **
- Axle length/shell width (mm)_XL118_68 (BC1.37): X **
- Axle length/shell width (mm)_XL118_73 mm: ✔
- Axle length/shell width (mm)_D-NL 122_68 (BC1.37): X **
- Axle length/shell width (mm)_D-NL 122_73 (BC1.37): X *
- Axle length/shell width (mm)_D-EL 127_68 (BC1.37): X *
- Axle length/shell width (mm)_LL123_68 (BC1.37): ✔
- Axle length/shell width (mm)_LL123_73 (BC1.37): ✔
- Axle length/shell width (mm)_LL113_68 (BC1.37): X **
- Axle length/shell width (mm)_MM110_68 (BC1.37): X **
- Spindle_Square type: ✔

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