Cracked seat tube?

[Fresh]

Noticed this tonight while inspecting my Cervelo S3...is that a hairline crack in my seat tube? I have barely ridden the thing in the time I have owned it...

[Duck!]

No, looks to me more like a join between two pieces of carbon mat in the layup.

[Comedian]

I'd go for join too. In areas that aren't painted you'd expect to see joins.

In the meantime - have a close look at it when you wash your bike to keep an eye on it, and when it's next in for servicing ask the Cervelo agent to check it.

[Nate]

yeah looks like join in carbon.
For a crack its just waaaay too straight.

Look at it in different light angles, does it come/go?
if you use a magnifying glass you may be able to see the fibres going around/in the crack.
How does it compare to other areas of the bike? similar patterns?

but yep - check it out at the shop.

[AUbicycles]

Can’t see well on the mobile phone so a second opinion is an external scratch (not crack) from a grain of sand (etc) that has scratched thr surface while the seatpost was inserted. It is perfectly centred so the other posters are probably closer.

[open roader]

I vote for carbon layup join line, my 2010 TCR Adv. had something similar running liner fair down the middle of the TT.

[Fresh]

Thanks for all the replies. The mechanic where I bought it agrees with all of you, and pretty much assured me when we noticed the join extend under the top tube with closer examination.

[Duck!]

Carbon frames are laid with literally several hundred individual pieces of carbon mat. The outer layer will generally be fairly large pieces wrapped around the length of the main tubes, especially if the frame is to be left clearcoated with a visible carbon finish, but there will always be visible edges between the pieces of mat.