What does this rod inside the my american classic seat post do? I've got an american classic seatpost. I bought it used, and wasn't sure how to properly adjust it initially. I found the bolt on the bottom clamps the seat down. The bolt on the rear underside adjusts the saddle angle. 

But the bolt on the front was a mystery. I took the post out and looked at it and you can see that the bolt on the front of the post connects to this rod inside the post.  

The rod has a fixed end which is inserted up in to the seat tube, and the bottom of the rod is threaded and has a small alloy knob on the bottom. It appears to flare at the bottom and has a slit in the bottom of the seat tub where this knob rests. I have no idea how you would tighten this from outsidem But it looks almost like you could tighten it like a stem for a treaded headset.

What is this for and why did they include this on the seatpost?

Seatpost


Close up of bottom of Seatpost with Rod (You can't see it, but there is a slit in the font of the seatpost)



Rod Removed from Seatpost


Bolt on front of Seatpost
I had a Peugeot bike once where the seatpost didn't have the usual clamp but a similar system to hold it in the seat-tube. The system was not very practical because if you wanted to adjust the saddle height you could only do so if the saddle was removed. The bolt was tightened from the top of the seatpost. There was a second draw-back: the seat-tube being rather thin walled you had to be be careful when tightening or you could ruin the tube.
Your bicycle has a normal clamp so I would remove this long bolt with the cone and save hassle and weight.