Symox

I have been using carbon paste and don't *think* I've ever overtightened it. However, just had a fitting done where the seatpost was raised significantly and noticed this raised "pinch" section (close to the seat collar). Not looking for a reason to spend money, so if its ok I can live with it.

Sy Reene

I'm no CF expert, but that don't look so good.

delbiker1 

You spent money on a bike fitting, but you do not want to spend money to replace an obviously damaged CF seat post. No one can tell you if that is safe from looking at a picture, IMO. Make your decisions and live with them, for better or worse.

Symox

Actually the fitting was free

Don't worry though, I decided to order an aluminum seat post to not take a chance

I'll probably cut up the carbon one to inspect and send pictures

SoSmellyAir

Yes, it is damaged. The question is how deep. I am no CF expert either, but this looks like paint or surface (i.e., epoxy resin) damage caused by the slot or notch at the rear of the seat tube; they even have the same shape. What happens if you press on the raised, wrinkled portion? Is it solid or crinkly?

Symox

It is solid, not crinkly

SoSmellyAir

Then it looks like you had tightened your seat post clamp hard enough for the slot to create an impression on the surface of the seat post over time. It is hard to tell how deep the damage goes unless you are willing to scrape / chip off some surface paint.

Symox

That's possible. Its also possible that since I used one of those bikepacking seabags that hangs 14lbs off the back of the seat. I suspect that might have been a mistake.

SoSmellyAir

On one hand, a 14 lbs. seat bag sounds really heavy; what do you put in there!? But on the other hand, what if you were 14 lbs. heavier and do not own a seat bag?

Still think that the culprit is overtightening because the crinkly raised portion matches the slot at the top rear of the seat tube.

Symox

14 lbs was tent, clothes, food and some other stuff for camping. But it sticks out quite a bit so there is a certain amount of torque and side to side "wag"

My theory is the flex of the seat post coupled with the carbon paste and possibly overtightening caused the raised section.

Litespud

They're your nuts.....

delbiker1 

IMO, good for you. I was not trying to be critical, just not worth chancing a failure while riding.

SoSmellyAir

If you are actually going to cut the post, why not just scrape, chip, or lightly sand off just the surface at the raised, crinkled spot to see how deep the damage goes?

By the way, that is quite a distance to adjust the seat post height on an existing bike you have been riding.

WhyFi

I had some CF bars that were left with the indentation from the stem/plate. It didn't look like that, though - it seemed to be limited to the clear coat and there were no cracks or distinct edges of the raised portions, which would have concerned me a little more.

Symox

I *think* it was just superficial, but better safe than sorry. I tried scraping first but couldn't tell so I just cut it up. Here are the pics. I have a new appreciation for the strength of carbon fiber after cutting it btw. The stuff is pretty sturdy!

Symox

I agree. He moved it forward a similar amount. Gonna take some time to get used to but what the fitter explained to me made a lot of sense (I was locking my arms in the old position)

SoSmellyAir

Did your fitter do the whole see if you can, without touching your handlebar, temporarily balance your riding position on your saddle to determine its fore/after position?

Sy Reene

I see your arrows, but none of them point to the circled area?

WhyFi

Look at the teeth marks. What you've circled is the last bit that didn't get sawn through.

Symox

No, that was the very last part of my sawing. I didn't make it all the way through cleanly so there was this bit sticking out

tFUnK

I see you've already cut it up but I was going to say I've ridden carbon posts with worse surface damage than that and they've held up fine. As you can see, they are pretty robustly built, but of course everyone's risk tolerance is different.