PMK

Do you guys have any suggestions beyond grease.

Trying to avoid anti seize on account of the mess.

PK

VaultGuru

Get assembly compound called Tacx. Here is the link for Competitive Cyclist. They carry it in a large size. Put it lightly on the seat tube, down the entire length of the contact point. Torque the seatpost binder bolt to <= manufacturers specs. Carbon is about 6.86Nm. Your problems should be solved.
https://www.competitivecyclist.com/za...26QUERY%3Dtacx

TandemGeek

You sure it's the seat post? Stoker's stem attachment, saddle clamp, eccentrics and a whole host of other things can be the source of what appears to be a seat post or stem-related noise if only because the sound seems to come from that part of the bike. It's amazing how sound travels around on a tandem, regardless of material. Carbon's the worst, I'd bet magnesium is pretty bad, aluminum is right up there too.

As Vault Guru notes, Tacx carbon paste is pretty good stuff at a reaonsble price so that's not a bad thing to have and use anyway. There is also FSA's Assembly Paste which is more expensive but even better stuff (larger spheres / more grippy). Somebody said that Finish Line had come out with yet another variation on this nano-technogy based compound. I still prefer Loctite 242 (blue) for bolts, but this stuff is pretty good for anything that has flat-face mating surfaces.

PMK

TG, some isolating of possibilities, by disassembling, lubing, then reassembly of most items mentioned, including the eccentric and drivetrain, have not resolved the noise.

What I did find was that when the sound occurs, we could stop, then loosen the capt's seat post clamp, rotate the post a 1/4 turn back and forth a couple of times, reposition and clamp. This would eliminate the noise for another 30 to 50 miles.

I don't have Tacx in hand so I have not tried it yet. Somehow I was under the impression this was more for preventing seat tube slip in carbon frames.

Our setup for the captain post is an oem aluminum Kalloy Sraph in the aluminum frame. I had been using Bel-Ray grease.

Not expecting it to last, on Sunday, I cleaned the post, masked it off and applied dry film lube (moly d). I hope I'm not jinxing myself but suprising it has been quiet since.

I'll see if the shop has Tacx or FSA in stock. Also any other successful lubes worth mentioning are appreciated.

PK

TandemGeek

As noted in the linked review of Tacx Dynamic Paste, "Essentially, the paste comprises tiny plastic balls suspended in a grease. The compound is designed to increase friction. How about that for a contrast, a lubricating compound that increases friction? The tiny plastic balls work as grit -- think compressible sand with smooth edges -- and that grit helps hold surfaces to one another."

These pastes don't really care what the materials being mated are made from so they work just as well at increasing 'bite' on carbon parts as they do on aluminum or titanium.

The rule of thumb for seat posts is, for a tight fit grease the interface... when it's a loose fit go dry. Your dry-lube and even these nano-technology assembly pastes would be the right way to go if your seat post is easy to remove and install: grease would, in fact, make slipping and 'creaks' more likely.

PMK

For lack of a better description, compared to all my other bikes, this one fits the same. Normal I suppose, not tight, but not loose.

The post however has a lot of length (260mm of its 350mm) inserted into the frame. With the stoker bars mounted to it, I was hoping to keep the seat/bars/frame as rigid as possible with the long post. As is the posts lower end is maybe 15mm above the weld for the diagonal tube. This would match your recommended the comment about a loose post vs tight post and whether dry or greased. Posts lower end is probably a much looser fit.

Still not totally certain of the exact source point, but possibly it's the posts lower end or some other oddity. Maybe the grease was wiping away as the post inserted where dry film didn't. Anyway, I'm just planning ahead if the creak returns.

PK

PMK

FWIW, and I hope I'm not jinxing myself, but, the post has been and remains quiet since the application of dry film lube.

PK