Surley cassette cogs are designed first and foremost for singlespeeding. At the base, the cogs are 4.35mm wide, which allows you to stack a few of them up for a simplified multi-speed drivetrain. Use a 9-speed derailleur if you do that.

• Machined from SCM415 Chromoly steel
• Heat-treated and chrome-plated
• Compatible with 6- to 9-speed 3/32" chains
• Available in 13t–22t