titanium seat tube galling?

[marciero]

I recently installed an aluminum seatpost on a titanium frame. It was very tough going in, so much so that I thought that something like galling might be occurring. Does that happen with seatposts? Should I remove and apply some type of paste or other prep as a precaution against that or seizing?

[berserk87]

Whatever the term, what you are experiencing is a real issue.

I use a light layer of anti-seize compound on my seatpost (I have a ti frame too).

Per the advice of a friend that is a long-time ti owner, I also remove and reinstall the post about once every six months. I clean it when I do and reapply fresh anti-seize compound.

[dave thompson]

Whatever the term, what you are experiencing is a real issue.

I use a light layer of anti-seize compound on my seatpost (I have a ti frame too).

Per the advice of a friend that is a long-time ti owner, I also remove and reinstall the post about once every six months. I clean it when I do and reapply fresh anti-seize compound.
^^very best advice^^

[fmradio516]

They make copper anti-seize for titanium applications. I belive Finish Line makes it. Ti-prep.

[bshell]

double check for proper diameter?

[marciero]

Thanks all. Diameter should be fine, listed as 27.2 on both post and seat tube. Will try the anti-seize.

[SPOKE]

27.2 is not always 27.2 when it comes to seat posts or seat tubes.

[marciero]

27.2 is not always 27.2 when it comes to seat posts or seat tubes.

Okay noted. Pretty sure the post is not oversized as it has fit in three other 27.2 seat tubes with no problem, so would have to be undersized seat tube if it were a sizing issue.

[sales guy]

The post might be right but the seattube might not be. Even new frames should have the seattubes honed. Even when I get them from my guys, I hone them anyways. It can't hurt. Always better to double check.

As for what you're experiencing, absolutely real. Galvanic Corrosion. two dissimilar materials essentially bonding together. Think of rust but not.

Finish Line does do a copper colored titanium prep. It works well. There is a silver colored one that marine and auto people use. I've tried it. Doesn't seem to work as well. I have many a jar of Finish Line ti prep. You can buy it in small ampules. It you need one, let me know and I can send one.

And yes, remove, clean and re-coat every few months. And remember, lube the hole, not the pole!

[11.4]

What you are sensing could not be galling, which requires heat, vibration, or substantial pressure to occur. This is a pedantic issue (my apologies) and you don't get galling in a situation like this.

What you do get, if you left it, is corrosion in one of the surfaces. A little corrosion causes a raise in the oxidized metal so it tightens in the fit. This has always been a reason for locking up bottom brackets in steel bottom bracket shells, seat posts in seat tubes, and so on.

As for your situation here, if this is nominally a 27.2 mm seat tube and seat post combination, it should stand to reason that both tube and post can't be precisely 27.2 mm. Typically seat posts are undersized by a few hundredths, and seat tubes are oversized by something in the same range. Some seat post manufacturers have asserted the right to measure precisely, lest users complain that their posts are undersized (which was a complaint for a while with Thomsons, as a case in point -- today they tend to be more precisely 27.2 mm for this size, which means the seat tube needs to be oversized). it's a bit of a pissing match between frame specs and seat post specs and one has to give or both have to. You can fix the problem by reaming the seat tube, but do be aware that if you end up oversizing it, you'll forever have a fit issue with different posts. There's no real answer to it; just don't do more harm as you fix the problem and don't let a shop necessarily ream out the seat tube without knowing absolutely that it was at fault.

With metal post and seat tube, always use anti seize. In a low-stress environment like a seat post and seat tube, frankly, you can use any anti seize. I always use the copper stuff just because it handles everything well and is less obvious as it smears all around, but you want to use quality anti seize (it's just grease with the appropriate metal powder in it, and if they use a cheap grease or too little metal powder, it's simply a crappy anti seize). I've found some pretty poor stuff coming from bike suppliers, so I tend to use products with major brand names and intended for real industrial use.

The grease in anti seize will last forever if it's well-made anti seize; it's realistically only when the grease dries out or contaminates that it causes problems. You'll never actually consume all the metal powder to prevent corrosion in an anti seize in a bike situation. In cycling, quite a lot of very experienced mechanics use high quality greases and don't worry about the metal powder because they know the grease is what makes or breaks it.

[thegunner]

What you are sensing could not be galling, which requires heat, vibration, or substantial pressure to occur. This is a pedantic issue (my apologies) and you don't get galling in a situation like this.

you can absolutely get galling with a ti seatpost and a titanium seattube without heat, vibration, or pressure though (i guess you could argue the friction generated by slipstrain on the seatpost is what's causing it).

that said i agree with the other posters that this is probably a tolerance issue.

[Climb01742]

I've found some pretty poor stuff coming from bike suppliers, so I tend to use products with major brand names and intended for real industrial use.

The grease in anti seize will last forever if it's well-made anti seize; it's realistically only when the grease dries out or contaminates that it causes problems. You'll never actually consume all the metal powder to prevent corrosion in an anti seize in a bike situation. In cycling, quite a lot of very experienced mechanics use high quality greases and don't worry about the metal powder because they know the grease is what makes or breaks it.

Are there any specific ant-seize greases you would recommend? Thanks!

[jumphigher]

Just adding that I wouldnt force a post in. Sometimes they just dont fit, despite being supposedly the correct size. Imo, you can damage the frame over time if a post is really jammed in there.

My steel road bike has a fairly tight fitting carbon post ATM, and in addition to it being greased I periodically move it. I think this prevents stuck posts if done fairly regularily.

[oldpotatoe]

They make copper anti-seize for titanium applications. I belive Finish Line makes it. Ti-prep.

Get some of this...less expensive than the same sort of stuff 'bike' packaged.

[marciero]

As for your situation here, if this is nominally a 27.2 mm seat tube and seat post combination, it should stand to reason that both tube and post can't be precisely 27.2 mm.


Good point. Neither can be exactly 27.2 in the sense that the probability that a given post or seat tube is exactly 27.2 is zero, so it makes sense that they should shoot for slightly less and greater, respectively.

Just adding that I wouldnt force a post in. Sometimes they just dont fit, despite being supposedly the correct size. Imo, you can damage the frame over time if a post is really jammed in there..

Of course, I sort of forced it in. And I've actually been through all this before with carbon post and aluminum many years ago. The carbon post on my Pinarello Prince was welded in there, and I can remember holding the saddle with my feet and twisting my Derosa Merak to get the seatpost out.


Get some of this...less expensive than the same sort of stuff 'bike' packaged.

I have something like this in a jar (I believe it's loctite) that I found in my father's garage years ago that I've been using to build wheels. I thought it would be good since it's sort of a grippy lube.

[Ozz]

Get some of this...less expensive than the same sort of stuff 'bike' packaged.

+1

Picked up a 6 oz bottle of this for about $9 on Amazon.....pretty sure it is a lifetime supply.

[marciero]

Finally got the post out. While I did not resort to frame upside down and standing on saddle, it did take every ounce of strength and about 20 minutes, taking 3-4 minute breaks every couple of turns. And it was only in about 12 cm.