Seat clamp is used to secure the seatpost when inserted into the bicycle frame. It comes with different diameter as each bicycle seat tube varies in its diameter.
It is important to note that the internal diameter of the seat clamp must be similar to the external diameter of the seat tube. Common sizes of seat clamp are 28.6mm, 31.8mm and 34.9mm.
There are two types of seat clamps
Quick Release Seat Clamp (Tightened using lever)
The most common type of bicycle seat clamp is the quick-release clamp. When the lever us released, the saddle can be adjusted accordingly.
Allen Key Seat Clamp (Tightened using allen key)
Allen key seat clamps are the more traditional style of bicycle seat clamps, using an allen bolt to lock the saddle in place on the seat post.
- External allen key seat clamp
- Internal allen key seat clamp
The tightness of the seat clamp is important for your safety.
- Too loose and it will cause the seatpost to move and slide downwards.
- Too tight and it will cause the seatpost clamp area on the frame to crack.
Important things to take note to ensure the proper usage of seat clamp
- Minimum insertion depth of 8cm on seat post is needed before the seat clamp can be tightened safely.
- Seat clamp to be placed in line with the seat tube of bicycle frame.
- Maximum torque is often written near the seat clamp area.
A quick release seat clamp is particularly useful if you share your bicycle with family members of different height or for children as they are grow up fast.
You can check out Decathlon’s bicycle accessories, they carry the three seat clamp sizes as mentioned in my article.
If your seat post is too short and does not meet the minimum insertion length of 8cm to allow it to be tightened safely, do consider upgrading to a longer seat post, also available on Decathlon.
Disclosure: If you do intend to purchase anything from Decathlon, I hope you can support Bike Guru by making your purchase via my affiliate link. Bike Guru will receive a commission and your kind support will help me in the cost of running this website to provide bicycling tips and advice for the cycling community.