Lebowski74

Apologies in advance for this, I looked for the answer online, I looked for a noob section on here.....

Shortly going to buy my first carbon road bike (likely a Supersix evo). Being retired and traveling a lot in our motorhome around Europe, to fit the bike in the 'garage', I have to constantly remove, or drop, the seat post. I don't like leaving the bike unguarded, so always store it away after a ride or at night.

The noob question is, would constantly dropping, or removing, and then re clamping a carbon post be likely to cause any problems?

Thanks in advance

PeteHski

It should be okay, but make sure you use a good torque wrench. Don’t rely on feel to clamp carbon.

FrankTuna

Don't think it'll be an issue, at least from my experience. I often use a Sram dropper post on my gravel bike (Salsa Cutthroat) for big rides, but swap for a regular post otherwise. Just keep some carbon grip paste handy and use a torque wrench.

easyupbug 

Cannondale will have very detailed assembly literature with that bike. I suspect they will spec grease or even assembly paste and so you will want to slide it out not down which keeps it from getting grease/paste all over the visible parts.

datlas 

Agree with above. Get a 5 n-m (or whatever the spec is) torque key and take seatpost out for stowage if it won’t fit.

Could you also fit by removing front wheel? That would be easier, possibly.

Iride01 

I haven't had any issues taking my carbon fiber seat post in and out multiple times for the trips I take it with me in the car to visit Colorado. Currently in my lifetime I have had more issues doing this with steel bikes. I've broken many a clamp bolt from overtightening them. And damaged many a clamp to where they won't any longer tighten enough to hold on to the seat post.

So far, I'm a little more careful with tightening the clamp on the carbon seat post. I don't use a torque wrench most of the time, but occasionally I'll get a torque wrench and remind myself what the 6.2 N-m actually feels like that my clamp has marked on it for the max. I suppose that similarly to the steel bikes, I'll eventually have some issues.

SoSmellyAir

Cannondale specifies 8 Nm for the seat post clamp (see. p. 16): 023151901canoms-supersix-evoen0803lr.ashx (cannondale.com)

This is higher than the more common 5 Nm or 6 Nm specified for many other bike components, and is thus more difficult to achieve by feel. I strongly recommend a torque wrench, especially since OP said this would be a first CF road bike.

My Cannondale uses a similar seat post clamp. If I had to remove the seat post (e.g., for storage or transportation), I would (a) remove the seat post and clean off any CF assembly paste residue, (b) cover the seat post hole in the frame with Saran wrap, and (3) add a little CF assembly paste to the clamp and the interior surface of the seat tube prior to installing the seat post.

tFUnK

I wouldn't make a habit of constantly loosening/tightening the seat post. Things wear, whether it's the seat post itself, the clamp, the clamp bolt, the inside of the seat tube on the frame, etc.

I've got a folding bike that requires loosening the seat post as part of the folding procedure. Over time I've worn out the seat post, the frame, and gone through a few clamps. Folks may say "you're doing it wrong" which is valid but the likelihood of misuse is high given that use case. For a traditional bike my philosophy is to set it and forget it.

If you constantly need to lower the seat post I would look into whether a dropper seat post might work. They don't drop the seat post all the way down but perhaps enough to help you.

Having said that, in the old MTB days before dropper posts were commonplace, we used QR seat post clamps and I didn't run into issues with repeated lowering/extending cycles for descents/climbs. Not sure this would work on the Supersix frame, though.

Sy Reene

Ok, but Cannondale has no idea what brand or torque rating that the seatpost you'll stick in there is rated for.

PeteHski

IME most people will tend to over-tighten a 5 Nm hex more than they would an 8 Nm or higher torque hex without using a torque wrench.

A good torque wrench is essential, especially when clamping carbon.

Mtracer

I would be concerned about wear and tear, even if using a torque wrench. Each tightening and loosen cycle is going to fatigue some of the parts. I have no idea how the carbon parts would react to this, but the metal clamp and bolt would fatigue. I have no idea if any problems would develop at 100 cycles, or 100 million.

Something like this cable-less dropper seat post might work. It has a lever right on the seat post. It will add some weight to the bike, but aside from avoiding possible wear to the bike, it would be a lot more convenient than removing the seat all the time.
TranzX Seatpost

tempocyclist

Thanks for the link! I'd not seen that sort of "under saddle" dropper actuation before. Might be an option for my gravel bike.

SoSmellyAir

The frame takes a specific Cannondale semi-aero seat post so I hope Cannondale has at least some idea about its torque rating.

Lebowski74

Thank you all for your replies and for being gentle with me, if I could find out how to like each reply, I would.

I am not afraid to admit I enjoy making sure everything works as well as it should and is torqued to the correct settings. I have an excellent torque wrench that travels with us when we go away.

It would seem the answer would be to take care and limit doing this as much as possible. Ideally I wouldn't do it at all, as I hate having to move a seatpost once it's set. Perhaps we just have to change our motorhome for one for a bigger garage! I'm on it....

Thank you all once again.

Iride01 

Participate in more conversations in other threads.

Once you get 10 post and maybe a day for the forum software to recognize it, you'll see a <like> button appear at the bottom right of each post.

You also get to post images and links in your posts when you get that magical number of 10 posts.

njkayaker

Grease isn't used for carbon seat posts. "Assembly paste" has "grit" in it to increase friction (grease reduces friction). Oddly. the "assembly paste" is expensive.

njkayaker

If you have to, use "assembly compound" and be sure to use the appropriate torque.

https://ultimatesportstrinidad.com/p...d-ahead-single

https://ritcheylogic.com/bike/access...rque-key-6-bit

easyupbug 

I only have two carbon frames with carbon posts and one is very tight and one typical. One is a Calfee & I follow a builder and carbon "expert" Craig Calfee position on the subject w/o ever having an issue:
Thankfully! An opportunity to dispel the myth that one shouldn’t grease a carbon post! I don’t know where the myth started, but carbon composites are not affected by grease. Our advice is simple: If the seatpost fits tight,grease it. If it slips, de-grease it. As has been known for many years, when aluminum and carbon fiber contact each other, galvanic corrosion can start. That is why Calfee uses a fiberglass sleeve as a seat tube shim. Aluminum seat tube (or sleeve) and a carbonpost will result in corrosion of the frame and possible seizure of the post within the frame. A carbon sleeve on an aluminum post will result in corrosion of the post. Salty environments accelerate this corrosion. Anodizing merely slows it down. About the only common chemical that will hurt carbon fiber is paint remover (which attacks the resin between the fibers). But there are many solvents that will dull a nice paint job.
Craig Calfee

PeteHski

If you are only removing the post when you travel then I wouldn’t worry about it. The clamp will have a relatively large surface area, so wear/fatigue should be minimal.

Some carbon posts/frames are more prone to slipping than others depending on design, so worth checking for any inherent problems with the specific bike you are buying.

People travel with bikes all the time and often have to remove the seat post. It’s not a big deal.

njkayaker

Interesting.

You really should provide the link to the source of quotes.

https://velo.outsideonline.com/road/...reased-carbon/

Anyway, Calfee also talks about being sure not to over-torque the bolt.

(The issue of aluminum and carbon together isn't the OP's situation.)

eduskator

I would recommend figuring out another way to store / transport your bike if this happens frequently. Not because it's not meant to be removed and reinstalled frequently, but because it may be less of a hassle. I would also recommend buying a good torque wrench and some carbon paste (what some members here call assembly paste) - it will become handy at a certain point if you remove your seat post too often as the paste will eventually wear off. It is pricey, but you don't need a huge amount if you apply it properly

Rule of thumb is:
Carbon to carbon = carbon paste
Carbon to metal = carbon paste
Metal to metal = grease

Sy Reene

Though, fwiw I've used paste in metal to metal from time to time. (e.g. saddle rail clamps on seatpost)

One watchout -- at least some pastes can be abrasive. Frequent removal/insertion can and will mar finish of some carbon components. Tape off at the insertion level at the very least to ensure you never insert too far and have to pull back up (which can mar a visible portion of your seatpost).

eduskator

Good point. It can certainly scratch bike parts such as a seat post if you're not careful. To my knowledge, they all contain fine particles of what seems to be sand to increase friction and decrease the tightening torque.

Camilo

I would recommend pulling the seat post out rather than dropping it. If you drop it and then raise it back up, the exposed part will soon look all scratched up. Mark the insertion point with a round of tape, remove the post,and then put it back in as far as the tape allows.

I'd also think kind of hard in using an aluminum seat post. I'm not paranoid about carbon fiber, but have the thought that aluminum might be less likely to be compromised by clamping and unclamping. Carbon probably won't be harmed either, but just thinking aluminum = cheaper and maybe less prone to damage.

FWIW, I'm of the opinion that although I have several CF seat posts, there really isn't a noticable difference between them and my aluminum seatposts. yeah, yeah yeah, the conventional wisdom is that they somehow absorb road noise and are more comfortable, but to me, the effect is miniscule, if at all after the saddle and tires are taken into account.

trashbiker

Carbon has no fatigue limit, so theoretically it would fail eventually. However, it can handle many times more load cycles than, for example, aluminum. Generally, fatigue failure is not a concern in carbon fiber components.

Not related to the quote: I believe carbon paste should only be used when the specified torque does not provide enough clamping force to hold the part or as a barrier between carbon and alloy parts. Carbon doesn't seize in carbon so no need for a barrier. The newest super-six uses a carbon post so I would try using the post without paste first. I doubt you will experience slip until the post wears slightly. That way you don't accelerate wear by having unneccesary carbon paste.