Bicycle seat posts, also known as seatpins, extend upward from the bicycle frame and connect to the saddle. They are adjustable and usually marked with the minimum insertion depth. It is essential to use the correct seat post length for your comfort. You may want to buy a seat post that is longer than the minimum insertion depth for your saddle size. To choose the correct seat post length, check the manufacturer's instructions or consult a professional bicycle mechanic.

You can adjust the seat post's length by using a seat post sizing rod. These rods have a scale marking the diameter. Place the rod inside the seat tube, and adjust the rod to the correct size. If you don't have a seat post sizing rod, you can cut a vertical slit into the seat tube to reduce the diameter and avoid the post from crumpling. Some clamps also come with a shim to fit a smaller or larger seat tube.

PJ-01 e-bike parts mountain bike parts bicycle seat saddle post

Product name	E-bike parts mountain bike parts bicycle seat saddle post
Product model	PJ-01
Product category	Bicycle seat post
Texture of material	Aluminum
Product tolerance	+/-0.1mm
Purpose	Fix saddle
Processing mode	CNC machining
Surface treatment	Anodic oxidation/powder coating/painting
Material	ALLOY
Diam	φ25.4-φ34.9mm