Bicycle Mechanics - Question about adjusting suspension seatpost

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Tom Bombadil
12-24-06, 01:32 PM
I picked up a 2000 Trek 7600 bike a few weeks ago. It has a Post Moderne suspension seatpost on it. Midway down on the post there is an adjustable ring collar. It has the appearance of being the mechanism for setting the stiffness of the post, if it is fully tightened the post's suspension barely budges with the hardest of impacts. When it is loosened a lot, the post has a lot of bounce to it.

However as I've not seen this type of adjustment before and a bike shop employee told me that he didn't think it was for adjusting the suspension, although he couldn't tell me what its purpose was. His comments have made me wary of loosening it. I did loosen it just a bit, which enabled the post to compress a bit under strong impacts and I liked it better that way.

So my question is, is anyone familiar with this type of post? It was a fairly common post a few years back, don't know how they are doing today, or even if they are still in business. Their web page is still dated 2005.

If you go to this page:
http://www.postmoderne.com/pst/product-index.htm

And down the left sidebar, click on "CUSHY-SE" that post looks like mine. It does say that it has a "One bolt side play control" which sounds like the tension collar does control the play of the post.

phoebeisis
12-24-06, 05:00 PM
KINDA IGNORE WHAT I HAVE WRITTEN IF IT DOESN'T FIT YOURS. My posts aren't exactly like any at the web site. I have two allen screws to adj side play,and one to adj preload(the site mentions allen key preload)
I recently came by two of these. It took a while, but I finally found how to adj it. There is an Allen bolt in the bottom; this adjusts preload, and is critical.
Those side adj are just for stiction.Have them as loose as possible without having much sideplay(oil them also).If they are too tight, it won't move much and the ride won't be improved.
Set the preload so it is just on the edge of moving with you in your natural riding position.There might be a way to shim the preload, if you can't adj it.
It took me a long time to figure the seatpost out. I've never has a sus. seatpost that actually seemed to work.THIS POST ACTUALLY WORKS. MAKE SURE YOU SET THE PRELOAD SO IT IS JUST ON THE EDGE OF COMPRESSING, BUT NOT COMPRESSING, WHEN NORMALLY SEATED!!
Luck,Charlie