Surly Stainless Seatpost Clamp Clamp it Down Need a seatpost clamp for your bike? Get one that's a little Surly. The Surly Stainless Seatpost Clamp is cast and polished and won't rust or chip paint because it can't (even the black ones!). They're shiny! They look good! And most importantly, they deliver the clampability that seatposts crave. It's available in both 30mm and 33. 1mm sizes. Features Cast and polished and won't rust or chip paint Available in both 30. 0mm and 33. 1mm sizes Compatible with numerous bike frames | Surly | Stainless Seatpost Clamp | Silver | 30. 0Mm