At what point does adding length to a shaft change the shaft's performance?

[TBS 682]

At what point does adding length to a shaft change the shaft's performance? (besides, its a longer shaft). 

Let's say you buy a used Auto flex or Oban shaft and want to add a 1/2" or longer. Is there any change in how the shaft works when you add length? Is the kick point at a different spot? I'm not super knowledgeable about how shafts work, but in my head, there has to be some change, right?

[NRJyzr 1,241]

Unless you add or subtract a lot of length of the shaft, you're not going to change the flex properties through length changes.  At a half inch, especially.  When you start making longer changes, what happens will depend on the profile of that particular shaft.  A shaft that is very butt-soft and tip-stiff will react differently than one that is very butt-stiff and tip-soft.

It also depends where you are adding the length, and how you're doing it.  Generally, tip trimming will make a shaft stiffer than if you reduce length by trimming from the butt section.

If you're taking an existing shaft and adding an extension to make it 1/2" longer, it's not going to change the flex.  It will result in a bit of backweighting, depending on the type of extension used.  Adding a half inch normally results in a three point increase in swingweight, but the weight of the portion of the extension inside the shaft will mitigate that somewhat.

Edited August 25, 2021 by NRJyzr

[kgglonghorn 8]

half inch