The Specialized Rear Rack Seat Collar (29.8 mm) is an aluminum seat tube clamp that lets you mount rear rack stays directly to the bike frame, even on bikes without built-in rack mounts. It features threaded inserts for a clean, secure attachment and works seamlessly with standard rack hardware.

• Seat tube diameter: 29.8 mm

• Material: lightweight aluminum

• Includes threaded inserts for rack stay mounting

• Intended use: add a rear rack to frames without rack mounts

• Finish: black anodized

• Compatible sizes: also available in 31.6, 31.8, 32.6, and 34.9 mm