# Is it possible to prove that applied forces to a top tube are worse than a seatpost when using a repair stand clamp?

This stems from the idea that you should use a bike stand clamp on a seatpost, if you can, for carbon fiber (CF) bike frames. Hopefully, this would avoid the cracking of a CF bike frame.

In order to prove that it's safer to clamp on a seatpost vs. a CF bike frame top tube, can we mathematically prove the acting forces on a top tube vs. seatpost is safer than the other?

• Regardless of the difference in potential damage that could be incurred when putting either location in the jaws of a repair stand, since a removable seatpost is an easily replaceable item vs. a frame, the seatpost wins on that merit alone. It is similar to a replaceable derailleur hanger. One of the derailleur hanger's true roles is to protect the frame of the bike by sacrificing itself if necessary (the other role is to serve as a mount point for the rear derailleur solidly and in alignment). Sep 29, 2023 at 20:05
• A second way to reason about it is that the seatpost is clamped in the frame while someone is sitting on the seat, and if it survives that load it should survive being clamped and supporting the weight of the bike. In any case, it's an engineering problem and mathematical proofs aren't a natural match for those.
– ojs
Sep 29, 2023 at 20:41
• This might be better migrated to Mathematics.SE if you want formulaeic answers, or engineering.SE.
– Criggie
Sep 29, 2023 at 21:37
• Duplicate of engineering.stackexchange.com/questions/56481/…
– Criggie
Sep 29, 2023 at 21:38
• @Criggie yup, sorry, I added that there since someone mentioned it would be better in the engineering stack exchange. Sep 29, 2023 at 21:47