thehammerdog

Titanium frame 27.2 size but seat post wont go down far then gets stuck!
Used good grease and 2 posts can it be corrosion? If so what do i do

freeranger

One possibility--do you have a water bottle cage on the seatpost? If you do, hold the post up against the seatpost and see if the bottom of the seatpost is above the mounting bolt for the cage. If it isn't, you need either a shorter bolt or cut off some of the seatpost.

Andrew R Stewart 

Have you removed the post and looked inside the seat tube for any internal issues yet? Corrosion, bottle bosses (as mentioned) welds? (As example is if the seat stays join the seat tube about where the binding happens then the weld distortion could be the restriction). How far will the post insert before it binds? If the post is anything but Ti then anti seize or assembly paste is better then grease at preventing future corrosion.

Was the bike new when you got it? if so how was the post's fit then?

The general minimum depth of a post's insertion is about 2.5" or so the post bottom end is below the top tube's joint, whichever is greater.

Whatever is done don't just go to a smaller diameter post as that will cause binder bolt area issues. Andy

Miele Man

Are you sure you don't need a 27.0 seatpost?

I bought a Columbus SL frame bike back in the mid-1980s and it too was speced for a 27.2mm seatpost. The post was quite tight and therefore the shop SLIGHTLY reamed the seattube. After that there was no more problem. The seatpost went into the seattube easily but was not oo loose either.

Cheers

dsbrantjr

Also make certain that the post or tube is not bent or kinked, even a small irregularity will cause it to bind. Try rolling the post on a flat counter or tabletop, with the clamp section overhanging the edge, of course.

thehammerdog

Frame is used Titanium spec is 27.2 never heard of 27.0 i read that ti and alum can cause corrosion is it best to use ti-post
i used some sandpaper on inside of post on the bumps seems to be better i think corrosion

Andrew R Stewart 

Can you restate this post? To use sand paper on the post insides does nothing for the frame. Your lack of experience with posts is evident, having never heard of a 27.0 size. Maybe you meant something else? With periodic maintenance galvanicly active materials can live together for years. Just look at all those steel frames with Al posts that still work fine. Andy

thehammerdog

Andy the word "uppity" serves you well.
I am sorry that your rigid thinking does not allow for any commonsense as to what I was attempting to communicate.
I used an abrasive material on the inside of seat post as I found what felt like small corrosion. The Titanium frame is older and used and has steel insert to protect the Ti frame.
Maybe take it down a notch as we are all not so rigidly anal in our approach to life on a community bike forum.
Have great day.

bwilli88 

Seat post attaches to the seat and slides into the seat tube. Sanding the inside of the seat post is a waste of time, sanding the inside of the seat tube when one finds corrosion or a burr is better. I use a brake cylinder hone to smooth the insides of my seat tube.

Correct use of names and terminology helps avoid confusion.

Andrew R Stewart 

I would sub "wanting good descriptive communication" for uppity. I work the service counter at Full Moon Vista (and of course the work bench too) and deal with this issue all the time. Yes I do have the ability to second guess what our customer is asking about most all the time. After 45 years one tends to hear all kinds of mixed up descriptions. Over the phone is sometimes the most interesting situations

But my point is to try to get people to really think what they are actually saying. (Just like we want with out politicians...) If your descriptions were to cost you time and money you might also wish for better terminology too.

I feel my first reply gives you the intent I have here on BF. We'll all just trying to help others. But when others can't describe what they did it's hard to do this help stuff. An added issue is your added detail of a steel sleeve in the seat tube (BTW are you sure it's steel? I've seen Al used for this sleeve often but never steel). The sleeve changes the options and possible methods of resolving your problem. (Ever listen to Click and Clack "the Car Guys"? Wait till you hear their response to missing info

Now that we know your ST is sleeved the option to ream it is more attractive as the sleeve isn't usually a structural member. I have known of a few Ti frames with a sleeve that had the sleeve replaced by the manufacturer (as in a send back for repair). One guideline I go by is to do the least reversible method last.

Any more details we don't yet know of? Andy

masi61

Remove the sleeve and clean it thoroughly. Check the sleeve to see if it has markings on it. It may be engraved or laser etched right on it the dimensions.

I have a sleeved titanium frame that uses a 30.0/27.2 sleeve.

These sleeves are are problematic. In my case my 27.2 post would allow the saddle to rotate slightly (but not drop down) and it would creak as well. I am using a Ritchey carbon post which is at the limit line. I really wanted to keep my post, I like it a lot. For me, I tried to get an accurate internal diameter on my seat tube interior using a metric dial caliper. I think the tube was a bit oval because one axis measured 30.0mm, the other axis was 30.2mm. I tried a 30.1/27.2 aluminum sleeve and it did the same thing (allowed the saddle to rotate sideways during rides, and it creaked). I then got a U.S.E. branded 30.2/27.2 sleeve that is Delrin plastic. This one is snug in a good way. My seatpost collar didn’t have to be tightened so tight that I risked snapping off the bolt.

But your problem is too tight a fit on the seatpost. So you need a thinner shim. Maybe only thinner by 0.1mm. There are Chinese made ones on eBay for less than $3 that you can try. Be sure to use copper anti-seize paste on the interface between the sleeve and the titanium frame.

Andrew in the previous post speaks the truth. He obviously has a ton of experience. Speaking for myself, I would say I am humbled when my lack of knowledge of a subject is laid out to me. Digging in your heels and perpetuating the same things that are preventing resolution of the issue is rarely the proper course of action...

3alarmer 

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....slooooowly I turned. Step by step, inch by inch....

Trakhak

delbiker1 

Andy, very nice reply. Not at all uppity or condescending, just making a valid point and trying to help. I am very impressed.