The Shimano Tiagra line of road components has been completely re engineered and remastered with a more refined ergonomic design. The Tiagra group shares Shimano’s top groups’ engineering lineage offering greatly enhanced feel and sleek design backed by new levels of performance.
Compatible with  9 speed chains with the Shimano Tiagra HG50 9-Speed Cassette. 

Features:

• 9-speed chain compatible
• Reduced cog spacing: 9-speed is same overall width as 8-speed
• Cassette Cogs: 11-25, or 12-23 
• Speeds: 9
• Chain Compatibility: 9-Speed
• Intended Use: Road, comfort,
• Drivetrain Spacing: Shimano/SRAM 9
• Cassette Body Type: Shimano 9

Sprocket sizes:

• 11-25T = 11, 12, 13, 15, 17, 19, 21, 23, 25T
• 12-23T = 12, 13, 14, 15, 16, 17, 19, 21, 23T