Shimano Altus FD-M315 MTB Bike 2×7/8 Speed Double Front Derailleur Top Swing Clamp 34.9mm/31.8mm

Option:
1, 34.9mm 
2, 31.8mm(34.9mm with adapter)
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Model: FD-M315
Level: Altus   
Speed: 2×7/8 Speed 
Compatible chain: HG 8/7/6-speed
Mount: Clamp-on 
Clamp Band size: 31.8mm/34.9mm
(31.8mm=34.9mm with adapter)  
Action: Top swing 
Cable route type: Dual-Pull(Top and down pull)
Top gear teeth: 36T 
Total capacity: 14T
Weight: approx 180g 
ACERA 2x8/7 speed front derailleur features a modified chain guide tail shape that increases tire clearance
One spec for 48.8 mm & 51.8 mm chainline