Tandem Cycling - Seatpost Q? Which app is better?

I want to get a CF seatpost. The alum bike came with a 29.8mm alum 350 long seatpost. The seatpost had a min. insertion of 150mm! Now that made me too low in the saddle, and my knees bent too much. So I bought a aluminum setback 400mm 29.8mm from Wiggle in the UK. But now I'd like to get a CF one. I'm not looking for weight savings, but comfort.

Best I can find is a Wound Up X-Post Carbon 29.8mm at 350mm long. (I have to find out what the min insertion on that would be.)

I could also get a 27.2mm 400mm and shim it.

I'm 220 lbs. Most other 350mm long seatposts that I've investigated are ok on the minimum insertion, and at 350mm, a seatpost would be below the bottom top tube weld point, inserted about 3.8 inches and about 1/2 below the lower weld.

So which would be better, strength wise, for the frame? A shimmed 27.2 400mm length or a exact fitting 29.8mm 350mm which is a little shorter.? I'm just worried for the frame at my weight.

Of course if anyone knows someone who sells a 29.8mm 400mm (or so), let me know.

Thanks\INDY

I have the Woundup post for my captain post - while others have - I wouldn't use a plain CF seatpost for the Stoker. The Woundup is nice because it is CF wrapped aluminum - providing alot of strength especially with the stem being clamped to it. My stoker uses a Specialized CF post with the zertz insert with a shim.

I have the Woundup post for my captain post - while others have - I wouldn't use a plain CF seatpost for the Stoker. The Woundup is nice because it is CF wrapped aluminum - providing alot of strength especially with the stem being clamped to it. My stoker uses a Specialized CF post with the zertz insert with a shim.


I have a Thudbuster ST on the stoker's position. But I'm surprised to hear that the wound up is carbon wrapped aluminum. The one bit of info I have on it ( www.bikemania.com) says nothing about that. I had a Bonti ACC carbon seat post and just didn't think it had that much absorbtion as a pure CF. Do you have a website for them? How did you get yours? LBS? Thanks!

(Go) INDY.

I don't find CF seat posts any more comfortable than Al. A CF post should always be tightened with a torque wrench. I like posts with infinite seat angle adjustment.
Sheldon