[Bob's Bikes]

Hope someone out there can answer this question, basically is there a minimum length the post has to reach UNDER the seat post clamp ie inside the frame or is it expressed as a ratio between the upper (exposed) length and the bottom (hidden) length.

I would assume that if you shorten the post under the clamp too much it might cause the frame to crack or split and obviously having a excessively long post in the frame is just wasteful.

Topic

[Batchy]

A good rule of thumb is that
A good rule of thumb is that the post should extend to below where the seat stays join the seat tube.

[racingcondor]

Yes, it’s usually marked on
Yes, it’s usually marked on the back of the post and around 8cm. Longer is certainly no bad thing though (although the extreme end or weight weenieism people do measure the minimum insertion and cut off the excess to shave off the ‘wasteful’ 10g).

[CXR94Di2]

longer the post inside frame
longer the post inside frame the better, fulcrum pivot point and all that. Weight saving a few grams only.

[Author]

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