alathIN

Spec'ing my new bike and wondering if I can get away with a carbon seat post.

I do use the tagalong fairly frequently, and sometimes even have a trailer behind that.

I have two kinds of tagalong - the Adams one, that uses plastic collars that actually wrap around the seat post and a circular clamp that goes around the collar, and a cheaper one that has a kind of two-sided vise attachment. I'm already sensing that the two-sided metal vise is not a great idea with a carbon seat post... but do you think I can get away with the Adams on a carbon seat post?

Alloy seat post is of course an option. But since my main purpose for this bike is long distance comfort, I would like the vibration-damping qualities of the carbon if possible.

DiabloScott

Adams recommends against it in their owner's manual.

I suspect you could get away with it for quite a while, and wouldn't notice when it started to break until it was too late.

How about two seatposts each with their own saddle? I have an extra seatpost for clamping into my repair stand.

Dream Cyclery

Just get extra cheap seatpost with a saddle and keep it with the trailer bike. Switch the post when you are using the trailer bike.

fietsbob

^^ this^^ for sure Kalloy's seat posts are reasonably priced and made in a bunch of different Diameters ..

Or get a Cane Creek Thudbuster suspension Post... pricy , but the Interchangeable elastomer pieces are made inn a bunch of rider weight ranges.

... since Butt comfort seems Important to You.. in long rides . Are you towing the young one on a Bike Tour?.

HillRider

Use an alloy seatpost. Does a carbon seatposts really have better vibration damping qualities than an aluminum post? Has the difference ever been measured? I believe it is mostly wishful thinking and marketing hype.

alathIN

@HillRider, good question. I've never had a carbon seat post on the same bike to compare.
@fietsbob, this is my 'do almost everything' bike. Commuter/tourer/family rides. We do some family bike camping but not that far.

dynaryder

NO! Friend of mine did that,despite the rest of us telling him it was a Bad Idea. Couple months later,he was riding into work(w/out the trail-a-bike),and his seatpost suddenly asploded. The sharp portion that remained in the seattube actually tore his pants,but luckily just scratched his leg. He mea culpa'd and switched to a metal post for using the t-a-b.

Seatpost,dunno. But I've def noticed a difference between a carbon and alloy bar. Also a difference between a steel and carbon fork,and a big difference between an alloy and carbon fork.

CliffordK

Is your seat post round or with some sculpted shape?

My Tag-a-Long requires one to remove the seat post to attach which was a bit of a pain, but it would be an easy time to change seats and posts.

There are also Tag-a-Long bikes that connect to a reinforced bike rack, but that would also depend on your bike setup.

FBinNY 

Buy two saddles and two posts, a CF one for solo riding, and a stout aluminum post for towing. Match the saddle positions and angles precisely, then put a collar, hose clamp, or at least a turn or two of tape, at the right height on each post. Then a changeover will take seconds and you'll have the best of both worlds.

That said, you're probably OK using CF post (though possibly not the lightest) to tow, if the clamp fits well and doesn't distort the post. Mount the clamp all the way down against the seat tube, so it produces the smallest a bending moment possible when towing.

Raiden

Is it a solid carbon post or just a carbon sleeve over an aluminum post? Tagalong bike is probably OK on the latter.

alathIN

Round.

rpenmanparker 

There is a well onown graph of test results that says yes. I can't look for it now, but lots of folks post it.

HillRider

If you can find that graph and post it, I'd appreciate it. I hear a lot about the "improvement" such-and-such makes but the data often shows the difference in favor of the object being touted is insignificant.

FBinNY 

I suspect that much of the hype about the relative shock absorption of CF vs aluminum posts is just that --- Hype. Of course any difference really depends on the amount of post showing, with the most benefit with the longest posts (showing).

OTOH- even with very long posts, I find it hard to believe that the vast majority of shock absorption isn't within the saddle rather than the post, so any difference will tend to be less significant in the general scheme.

Then, of course, there CF posts designed with shock absorption, such as the specialized post, but that's a horse of a different color.