This shim will let you easily fit the 31.6mm ShockStop City 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.
• 31.6mm seatpost size can be adapted to 34.9mm outer diameter (seat tube diameter)
• 100mm (4-inch) length spreads out clamping load along seatpost and frame
| Weight | 27.2-28.6mm - 16 g |
| Length | 100 mm (4 inches) |
Different bikes sometimes have different seatpost diameters. The ShockStop Seatpost and Dual-Position Seatpost are both 27.2mm in diameter, so if your bike's seatpost is larger, you'll need a shim to adapt our seatpost to your bike's frame. Don't worry though, the shims are super-lightweight and essentially invisible once installed.
Not sure what size seatpost you have currently? There are a couple different ways to find out.
• Most seatposts have the diameter printed somewhere near the bottom of the post. You'll need to remove the seatpost from the bike frame (mark your existing seatpost height with a bit of tape before you remove it so you can replace it easily), and look for a number like 27.2, 30.9, or 31.6 (etc.). That is the diameter of the post.
Non-compatible posts: Unfortunately, if your bike's seatpost is smaller than 27.2mm (for example, the 25.4mm posts found on some recent model Cannondale Synapses) our seatpost is currently not compatible with your bike. Likewise, if you have a bike with an aero/oval/non-round seatpost, or if your bike has an integrated seatmast, the seatpost is also not compatible.
