djpfine

Why do some carbon bikes come with aluminum seat posts? Doesn't this somewhat negate the benefit of carbon? My entry-level Giant Defy comes with a carbon seat post, and I find it odd that a few of the mid-range carbon bikes I'm looking at come with aluminum.

Elvo

They are cheaper and Thomson Masterpieces are lighter than some carbon posts.

abstractform20

kind of weird, but im sure it saves money for the company.

zachsilvey

Seatposts, like bars and stems, are more prone to failure when made of carbon because of the clamping forces on them. I was in my LBS the other day and a guy brought in a Madone with a snapped seat post. He said it happened when he was hammering in the saddle.

abstractform20

id bet that the seatpost clamp was too tight.

composites can be made ridiculously strong.

M_FactorX19

im sure they do it to save cost but the thing is you cant tell a difference in ride quality between a carbon or alu seatpost. so why does it really matter?

abstractform20

depends upon quality and rider perception.

that being said, carbon can be processed to be more forgiving than aluminum.

M_FactorX19

ill agree with that but its just doesnt make that big of a difference in a seatpost. it wasnt to long ago i went from a house brand alu post to a high end carbon 3T post and it didnt make one bit of difference in ride quality. it was lighter, looked better, and had the offset i wanted though.

rolliepollie

Only differences in seatposts are weight, clamp style, looks, and weight. Yes, I said weight twice.

guadzilla

That makes no sense. When I hammer really hard, I have next to no weight on my saddle. Even if I do, I am not ramming my ass up and down on the saddle. How the hell does hammering cause a seatpost to break? Handlebars and stem - I can atleast understand the concept, but a seatpost?

UCIMBZ

Not true. Here is a highend prefessional bike from Team Exergy with alloy bits all over including the Microshift drivetrain. The concept of performance is totally convoluted in this sport.
https://teamexergy.com/new/homepage/felt_f1/

AChristie

I switched to Alu from carbon so there's a safe place to clamp my workstand.
I"m sure the warnings about clamping on carbon are overblown, but why take a chance?

Absolutely no difference in ride quality. Unless you're a "princess and the pea" person.

urbanknight

The last time I had a carbon bike, there was no such thing as a carbon seat post.

I figure it's because of how easy it is for a newbie to tighten the clamp too tight.

topflightpro

First of all, a lot of low end carbon posts aren't really carbon - they're aluminum wrapped in carbon to look like they are carbon. There is a good chance that your Giant Defy has such a post.

Secondly, while bike shops like to tell people that carbon posts soften the ride, they don't really do much. In fact, I'm running a Thomson post on my Cannondale System Six (aluminum rear triangle, carbon front) and a carbon post on my Caad 9, and I cannot tell a difference. So, weight is the big advantage from a carbon post.

And as for the Madone, did the post break or the mounting bolt? I have a buddy with a Madone and he has broken two or three mounting bolts on the seat pots caps. I think they have a manufacturing or design flaw.

Adrianinkc

+1 My specialized allez has this.

Palomar01

A good quality CF seat post does make a difference. It's slight but it absorbs more vibrations than an aluminum seatpost of equal value. It also has this characteristic of not acting like a tuning fork like metal tubes do. The CF absorbs those high frequency vibes that metal likes to pass on. Thus, overall sensitive people will notice the CF material rides "quieter". An alloy seat post or stem wrapped in CF gives you the look of carbon and it too absorbs those high frequency vibes. It just won't be as light as the high quality CF stuff.

What does make a big difference in ride quality is the frame design, tire size, and seat cushion. It's possible to make a good AL frame designed for comfort, ride as good as an entry level CF frame. Go ride a Synapse alloy or Specialized Secteur alloy and see for yourself how nice they ride. Those bikes have a lot of the feel of CF frames. Having said that, the high end CF frames ride even better. This is why the Roubaix's and the Synapse CF's have made names for themselves.

djpfine

I've been tricked! Looks like marketing wins again...

urbanknight

Anybody know about the one that comes with a 2010 Allez Elite? It's black throughout, and I can't see any transition from one part to the next, but the inside sure feels like aluminum to me. No matter, since it's the wrong setback for me, but I'm curious anyway.