What size seatpost clamp do I need?

Note: The seat clamp diameter needs to match the diameter of your seat tube rather than your seatpost, which is a little smaller. For example, a 27.2mm seatpost (a size commonly found on road bikes) fits inside a 28.6mm diameter seat tube, so it’s a 28.6mm clamp you need.

What size clamp do I need for a 28.6 seatpost?

Size & Use: Two types of bike seat post clamps are available while seatpost clamp 31.8mm applies for 27.2mm / 28.6mm (outer diameter) bicycle frame seat tube, and 34.9 mm seat clamp suits for 30mm/30.4mm/30.8mm/30.9mm/ 31mm/31.6mm (outer diameter) seat post.

How do I know what size my seatpost is?

To find out the diameter of your seatpost, you must remove the seatpost from the bicycle frame and look for the size, which is stamped just below the “Minimum Insert” line toward the bottom. The number will be a three-digit number (such as 26.8 or 27.2 or 31.6).

What is the standard size seatpost?

While there are any number of post diameters out there, most modern road and MTB bike frames accept a seatpost of either 27.2mm in diameter (‘standard’), 30.9 or 31.6mm (‘oversize’).

What size seat clamp do I need for a 25.4 seatpost?

25.4 seatpost = 28.6 seatpost clamp.

Can a 31.6 seatpost fit a 30.9 frame?

You can fit a narrower post into a wider frame using a shim (a thin sleeve of aluminium or plastic), for example a 30.9 mm dropper post into a 31.6 mm frame. However, there is no way to fit a wider post in a narrower frame, for example a 31.6 mm post into a 30.9 mm frame.

How do you install a standard bike seat clamp?

  1. Step 1 – Line up the inner plates. Remove the spindle and side plates. Take one of the inner side plates, place it against the clamp and put it on the rail.
  2. Step 3 – Hand tighten the hardware. Install the outer plates and spindle.
  3. Step 4 – Attach to the seat post. Attach the seat and clamp to the post.

What is a seatpost shim?

Seatpost shims are short pieces of tubing, usually made of PVC, thin aluminum or steel, used to increase the diameter of a seatpost. Shims have a cutoff which makes them expandable and facilitates the installation process.