Do Campy carbon seatposts still suck?

[shinomaster]

I might want to get one for some more set back, and was wondering if they did in fact, fix the problem?

[cookieguy]

I was nervous myself...my LBS indicated that they had not seen any failures since '01 and that most of their problems were with posts that barely had more the than min amount left in the frame. If I recall recorrectly, in '04 they recommended using the longer length post (a whole couple ounces heavier!!!) instead of the regular post to be extra conservative. With me being short and light, and well mannered, not even a hint of a problem.

[saab2000]

I have a 2001 Record Carbon on my Merckx. No problems yet. There's at least a quarter inch left in the frame. Maybe even 5/16.

Some people who had failures had clamps that caused some problems.

[slowgoing]

The problem I experienced was it was too easy to overtighten the frame clamp on the carbon post. I did so unintentionally, and the post broke into these amazingly sharp shards. Although I was transferring it from bike to bike quite often. Maybe if you kept it on the same bike all of the time it wouldn't be a problem. I don't use carbon seatposts anymore.

[The Spider]

I've been using them since 03, so from my side of the world...they still rule!

Strong, light, adjustable, good amount of set-back, nice looks, one bolt adjustment (V. Important). The Record posts have it all.

I actually asked Dario to spec a seat tube just so I could use a 31.6mm post with the Campagnolo in mind. That good. :)

[buechse]

I was using a 2001 Record Carbon seatpost on my Colorado III without the slightest problem. At 65 kilos I'm not the heaviest rider but I never had the feeling that the post might be weak.
I'm also considering a Campy Carbon seatpost for my Nove (that should be delivered this week :beer: !), even though the new bike will have a sloping TT and therefore a longer seatpost.

Best regards,
Peter

[Bill Bove]

I've been using them since they were introduced, never a problem. And I'm no flyweight either.

[chrisroph]

Yes, thomson, ritchey......DA, superbe, ac.....

[Tony Edwards]

I don't want this thread to be entirely curmudgeon-free, so I'll ask: what is the point of carbon seatposts, exactly? Are rakish good looks and infinitessimal weight savings enough to offset the slipping and the small but real chance that the post will break, and you'll end up core-sampling your own butt cheek?

<------- Loves his Chorus ti seatposts

[saab2000]

I agree with Mr. Edwards. But my gruppo came with one. I like metal posts better and wish that Thomson made one with a the same setback as Campagnolo. I would buy one.

[chrisroph]

Saab, agree. I cannot use thomson posts without 72 deg st angles, except for the track bike and the mtn bike.

[Hysbrian]

I've used one for over a year. About a year on the Six13 and a few months on my Peg (with a shim) and haven't had a single problem. Whats wrong with a carbon post when its just as good as a metal one???

[e-RICHIE]

I've used one for over a year. About a year on the Six13 and a few months on my Peg (with a shim) and haven't had a single problem. Whats wrong with a carbon post when its just as good as a metal one???


nuttin' honey.
i heart my cf post.

[chrisroph]

When I bought my merckx al, it came with 2 carbon posts, a bontrager that was cracked and a no setback something or other that would not allow me to put the saddle in the right place. It's now wearing a ritchey 2 bolt post. I would have tried one of them if they had worked.

[Hysbrian]

nuttin' honey.
i heart my cf post.

we all know what happens when you take the CF off road...just ask Tyler.

[stevep]

the big issue with carbon posts is that people overtighten them to hold them in place... the extra torque can bring the popst very close to the amount it can tolerate before cracking/ caving in and failing.
they may need to be "overtightened" becaus they are kind of smooth and pretty slippery.
tacx now makes a carbon post " treatment " that is grease with some texture that allows the post not to slip and slide at lower torque. a very good product that will help carbon posts to live longer.
i dont want to get into a "never grease the carbon post " issue here... but they will freeze so solid if not greased and a non acidic grease wont hurt that stuff.

[steelrider]

If you can track down a used Ti Campy post on Ebay, you will be stoked. The setback offered is sublime. I really like Thomson, but the setback version is ugly.

[e-RICHIE]

we all know what happens when you take the CF off road...just ask Tyler.


film at eleven atmo

[nobrakes]

There is no seatpost material in current use that can't be destroyed by ham-fisted over torqueing. If a person consistantly is damaging seatposts from over-tightening, I would suggest putting the tools away and let a mechanic do the job. Or buy a torque wrench, better yet, try a post made out of solid steel. That said, I've got an '01 Record carbon post still going strong, and I use the seatpost collar that it came with. I have an FSA carbon in an all-carbon bike, and a ITM carbon in an aluminum bike all with out any problems or slipping down. I don't grease them, but fear they could freeze up in the frames, especially the aluminum or steel frames, so I try to regularly loosen and take the posts out of the frames and wipe them down, pour out the accumulated water (it's rainy here). I've seen carbon posts "rust-welded" into steel frames, and "corosion-welded" into alu frames. Don't know about titanium, but I've heard aluminum posts can corode and fuse into ti if you don't grease them.

[xcandrew]

Dimensional tolerances of seat posts and seat tubes are not that great in general. If you take some calipers to a bunch of seat posts and seat tubes, you'll see that that is true. Seat tubes are often not perfectly round from welding or brazing heat. Think about what happens with a slightly under dimensioned seat post (common). The hard edges of seat tube slot have to pinch in on the post before the post is fully secured. That pinch just means a lot of pressure concentrated in that small area, something that carbon is not very tolerant of. If the frame has a built in seat clamp, the pinch will be be even more severe if the post is small because there is more pinching leverage. That is why you often see the recommendation to reverse the collar for frames that use separate seat collars.

If a seat tube was perfectly smooth and round inside and perfectly matched to a seat post of the same actual diameter (example: 27.20 mm seat tube with 27.20 seat post), you would be able to stick the post into the tube, and be able to get from loose to fully tight with a single turn of a wrench (or something like that).

With a "27.2" seat post that is actually, say, 27.14 mm, you're going to turn that wrench and the initial resistance is coming from bending the seat tube in towards the post. In other words, you will feel resistance, but the seat post is still loose. As you turn the wrench further, you will be both getting the post tight and working to bend the frame tube further (conforming it to the post plus some pinching in). What am I trying to say with this? Well, the amount of torque needed to fully secure the post so it holds your weight (even on seated bumps) will vary depending on how undersized the post is and how stiff your seat tube is in the clamp area. If you go by torque wrench, what happens is that the post is sometimes not tight enough to be functional before reaching the recommended limit (thus the varied advice to patch the problem by using or not using grease and other substances, sanding, etc. - but none address the root problem). That recommended limit is also not an actual measure of what will protect the seat post. It's not difficult to imagine scenarios where the local stress on the post at the slot can be too high even within the recommended torque limits.

For those reasons, I think that people who are cracking their posts are likely just doing the perfectly reasonable thing - tightening their posts until they don't slip and no tighter. I doubt that they are as ham fisted as many of you are suggesting. I think that carbon parts to be clamped should be designed for real life tolerances, whether reinforced in clamping areas or thick enough in general to avoid the problem, but it seems that most aren't. I don't think it's realistic to expect that the tolerances for seat tubes and posts will get tighter, so I think that going for carbon seat posts is kind of just looking for a problem. But if the inside of your seat tube is round and smooth enough, and the post fits tightly, you will be wondering why others have problems.

[classic1]

+1

[stevep]

hes right... in a long story kind of way

[Darrell]

Dimensional tolerances of seat posts and seat tubes are not that great in general. If you take some calipers to a bunch of seat posts and seat tubes, you'll see that that is true. Seat tubes are often not perfectly round from welding or brazing heat. Think about what happens with a slightly under dimensioned seat post (common). The hard edges of seat tube slot have to pinch in on the post before the post is fully secured. That pinch just means a lot of pressure concentrated in that small area, something that carbon is not very tolerant of. If the frame has a built in seat clamp, the pinch will be be even more severe if the post is small because there is more pinching leverage. That is why you often see the recommendation to reverse the collar for frames that use separate seat collars.

If a seat tube was perfectly smooth and round inside and perfectly matched to a seat post of the same actual diameter (example: 27.20 mm seat tube with 27.20 seat post), you would be able to stick the post into the tube, and be able to get from loose to fully tight with a single turn of a wrench (or something like that).

With a "27.2" seat post that is actually, say, 27.14 mm, you're going to turn that wrench and the initial resistance is coming from bending the seat tube in towards the post. In other words, you will feel resistance, but the seat post is still loose. As you turn the wrench further, you will be both getting the post tight and working to bend the frame tube further (conforming it to the post plus some pinching in). What am I trying to say with this? Well, the amount of torque needed to fully secure the post so it holds your weight (even on seated bumps) will vary depending on how undersized the post is and how stiff your seat tube is in the clamp area. If you go by torque wrench, what happens is that the post is sometimes not tight enough to be functional before reaching the recommended limit (thus the varied advice to patch the problem by using or not using grease and other substances, sanding, etc. - but none address the root problem). That recommended limit is also not an actual measure of what will protect the seat post. It's not difficult to imagine scenarios where the local stress on the post at the slot can be too high even within the recommended torque limits.

For those reasons, I think that people who are cracking their posts are likely just doing the perfectly reasonable thing - tightening their posts until they don't slip and no tighter. I doubt that they are as ham fisted as many of you are suggesting. I think that carbon parts to be clamped should be designed for real life tolerances, whether reinforced in clamping areas or thick enough in general to avoid the problem, but it seems that most aren't. I don't think it's realistic to expect that the tolerances for seat tubes and posts will get tighter, so I think that going for carbon seat posts is kind of just looking for a problem. But if the inside of your seat tube is round and smooth enough, and the post fits tightly, you will be wondering why others have problems.

Spot on!

[shinomaster]

For some reason I don't think it would work as well in my Atlanta as it would in my cannondale. No disrespect toward my atlanta clamp, but it seems that I have to tighten it a lot to get it to hold a post in place. There were no carbon posts around back when that frame was designed.

[The Spider]

If a seat tube was perfectly smooth and round inside and perfectly matched to a seat post of the same actual diameter (example: 27.20 mm seat tube with 27.20 seat post), you would be able to stick the post into the tube, and be able to get from loose to fully tight with a single turn of a wrench (or something like that).

But if the inside of your seat tube is round and smooth enough, and the post fits tightly, you will be wondering why others have problems.[/QUOTE]


absolutely....the seat tube of my Parlee is so perfectly round (or perfectly matches the Campagnolo seatpost in roundness) that it makes a popping noise of decompression (seatpost and settube are filled...no holes!) when removed! quite strange the first time it did it!

[shinomaster]

If a seat tube was perfectly smooth and round inside and perfectly matched to a seat post of the same actual diameter (example: 27.20 mm seat tube with 27.20 seat post), you would be able to stick the post into the tube, and be able to get from loose to fully tight with a single turn of a wrench (or something like that).

But if the inside of your seat tube is round and smooth enough, and the post fits tightly, you will be wondering why others have problems.


absolutely....the seat tube of my Parlee is so perfectly round (or perfectly matches the Campagnolo seatpost in roundness) that it makes a popping noise of decompression (seatpost and settube are filled...no holes!) when removed! quite strange the first time it did it![/QUOTE]

Cool...tight tolerances are neato...inmho.