What it does and why you need it Seatpost reducer sleeves let you install a smallerdiameter seatpost into a larger seat tube without buying a post. This saves cost and time when upgrading or swapping seatposts, and avoids damaging the frame by forcing mismatched parts. The adapters maintain correct seatpost alignment and secure spacing so your saddle height and angle remain stable after conversion. Key features Function: Tube shim / bushing adapter for converting seatposttoframe diameter. Material: strength aluminum alloy — lightweight and corrosionresistant for reliable everyday use. Weight: Approximately 25 g per sleeve for minimal added mass. Size: 60 mm length, 34.9 mm outer diameter, 40 mm inner height; engineered for secure spacing and consistent alignment with minimal measurement deviation. Compatibility Supports common seatpost conversions including: 22.2 mm to 25.4 mm 25.4 mm to 27.2 mm 27.2 mm to 31.6 mm 31.6 mm to 33.9 mm Also suitable for frames and seat tubes compatible with an outer diameter of 34.9 mm as indicated by the sleeve dimensions. Performance and durability Precisionmachined inner and outer surfaces ensure a snug, slipresistant fit and smooth installation. Aluminum alloy construction resists wear and corrosion under normal use while keeping component weight low. Typical use scenarios 1. Replacing a damaged seatpost with a different diameter post after a crash or wear, without replacing the frame or buying a seatpost. 2. Upgrading to a lightweight performance seatpost that has a smaller diameter than your existing frame's seat tube. 3. Swapping a single preferred seatpost between bikes with different seat tube sizes for travel or multibike setups. Notes for installation and fit Verify the exact seatpost and seat tube diameters before installing to ensure the correct reducer size. Clean mating surfaces and inspect for paint or debris that could affect fit. Tighten to manufacturer torque recommendations for any clamp hardware. Minimal measurement tolerance is expected; if fit feels loose or excessively tight, recheck sizes or consult a bike mechanic. This adapter provides a simple, lowcost solution to bridge diameter differences while preserving alignment and ride quality.