Aluminium seat post - titanium frame

spanner239

As per title, what to use, grease, anti seize, carbon assembly paste??

It is a Deda Zero 100 aluminium post in an Enigma frame.

Maybe I should just bite the bullet and get a carbon post????

flasher

Light smearing of grease should be fine, I've Deda ally seat posts in both my Ti bikes, no problems.

term1te

Yep, a bit of grease, I've had a Thomson aluminium seatpost in my titanium frame for the last 8 years with not problems at all.

Matthewfalle

Copper slip will do the job nicely - the little granules in it will also grip nicely as per carbon paste meaning reduced torque values required.

spanner239

Thanks guys, my only other concern is if I do decide at some point in the future to go carbon, how difficult would it be to clean out the grease before fitting it?

Matthewfalle

Not difficult at all - stuff a rag down there, wipe it all out. If too deep for fingers wrap rag around something like a broom handle and stick that down there.

Even if there is a bit of residual grease in there it doesn't make an iota of difference - grease in no way at all affects carbon.

spanner239

Many thanks, I will try not to be too OCD!

Matthewfalle

No!!!!!!

Be OCD. It is the only way (says utterly OCD man )

OCD is good.

bondurant

I thought grease did affect carbon fibre, or at least could do.

Someone should google this for me.

bondurant

Back on the original topic; you will often find an aluminium sleeve in a ti seattube in any case. I always use copaslip to avoid binding, so far so good.

Matthewfalle

Bondurant wrote:

I thought grease did affect carbon fibre, or at least could do.

Someone should google this for me.

No it doesn't at all. Ever ever ever ever ever. Never.

If it did you would never be able to build anything with carbon. No bikes. No cars. No aero planes. No space ships. No ships. Nothing. Nada. Nil. Rien. No motor bike parts.

Now, rain water, there's a different subject.

Matthewfalle

Bondurant wrote:

Back on the original topic; you will often find an aluminium sleeve in a ti seattube in any case. I always use copaslip to avoid binding, so far so good.

This is the correct answer. Chapeau.

bondurant

Knew I'd read something somewhere. Can't believe I was forced to google it myself.
http://www.bikeradar.com/forums/viewtopic.php?t=12534958

I don't know the truth of the matter.

sungod

Bondurant wrote:

Knew I'd read something somewhere. Can't believe I was forced to google it myself.
http://www.bikeradar.com/forums/viewtopic.php?t=12534958

I don't know the truth of the matter.

manufacturers of carbon fibre bikes and components that are regularly coated in oil, grease, whether by accident or design, say not to use it, but aside from a mention of 'acidity' and some mysterious 'minerals', none give any chemically specific explanation of why it's an issue, just vague tosh with a heavy serving of qualifiers

it's going to be really tough using those campag cf rear mechs with no lube, whatever were they thinking using such an unsuitable material?

reality:

a) stuck cf post in al frame, electrolytic corrosion, specifically due to the differing galvanic potential and the increased volume of the resulting corrosion products

b) cf post in al frame not sticking, used cf assembly compound, which is grease-based, thus protecting the surface from corrosion and also reducing required clamping force


if zinn had asked a materials scientist with competence in the field about it, the article could have been useful, but instead he asked manufacturers/distributors in a country notorious for spurious litigation if grease could be an issue, and got a predictably risk averse "don't sue me" response


as matthewfalle says above, there's no problem, that article is full of nonsense, even it's writer subsequently says there's no problem with grease on cf...

http://velonews.competitor.com/2009/10/ ... post_99640

crankycrank

Another article with a response by Craig Calfee of the super high quality (and super expensive) Calfee CF frame maker fame. Also an American based in lawsuit happy USA. http://velonews.competitor.com/2005/10/ ... arbon_9023 Says grease is not a problem. I would trust this guy.