A seatpost shim lets you easily fit the 27.2mm diameter ShockStop Seatpost OR Dual-Position Seatpost into your larger seat tube. DESCRIPTION This shim will let you easily fit the 27.2mm Dual-Position Seatpost or ShockStop Seatpost into your larger seat tube. Just drop the shim in your frame's seat tube and insert the seatpost. Once installed, the shim is essentially invisible. DETAILS Fits 28.6, 29.8, 30.0, 30.4, 30.9, 31.6, and 31.8mm outer diameter Fits 27.2mm inner diameter 100mm length spreads out clamping load along seatpost and frame TECHNICAL SPECIFICATIONS WEiGHT 27.2-28.6mm - 16 g27.2-29.8mm - 30 g27.2-30.0mm - 33 g27.2-30.4mm - 36 g27.2-30.9mm - 43 g27.2-31.6mm - 52 g27.2-31.8mm - 55 g LENGTH 100 mm FAQ Can I use a shim to adapt to a non-round or "aero" seatpost? Unfortunately, the seatpost shim is only designed to adapt our 27.2mm round seatpost to other larger round seatpost diameters (for example, 31.6mm or 30.9mm). If your seatpost is oval or "aero" shaped, then both of our seatposts are not compatible with your bicycle. My bike has a 25.4mm seatpost. Do you have a shim for that size? The short answer is no. Both of our seatposts are only available in 27.2mm diameter. Since that is larger than 25.4mm, it is not possible to use a shim to adapt the seatpost to your frame.
