Steel bike seat post clamp tight but seatpost slipping

[R3awak3n]

This is a bit hard to explain but having seatpost slipping issues after removing the seatpost to grease it. The ears in the seatpost clamp were always very close to each other (frame was used, they almost touch) but there was no seatpost slipping so I ignored the issue. Just removed the seatpost to grease it up and now there is seatpost slippage. I do not want to tighten the bolt more since the clamp will touch each other and will not tighten more and afraid to mess things up more than they seem to be.

Wondering, is it possible I have the wrong seatpost? 27.2 chorus titanium, fits the frame perfectly, does not more around when its inserted, its not difficult to remove but not easy either, almost 100% the frame takes a 27.2.

Or should I shim? Maybe the seatpost is too thin? I never measured it but bought it as a 27.2 (don't think there was a 27 version of the titanium post).

Appreciate the help

[Black Dog]

Try friction paste (carbon paste) 1st. (it will also prevent corrosion like grease does). If that does not work then I would consider a shim; beer or soft drink cans make good shims.

[R3awak3n]

The bike is just too nice to shim :) My guess is that the old owner or owners tighten the clamp too much

[Tony T]

Might be worth trying a new clamp.

[soulspinner]

Try some carbon anti seize ....

[R3awak3n]

Might be worth trying a new clamp.

Its not a removable clamp, I wish it was. Its a vintage bike, clamp is build in the seat tube

[p nut]

I would double check that seat post or try another 27.2 post. I had a similar situation a few years ago. I ended up breaking the binding bolt, as the ears of the clamp touched. Well, turned out to be a 27.0 seat post (:crap:). Guess I couldn't tell a 0 from a 2 when it was covered in dirty grease.

I doubt that cranking the binding bolt down caused the steel clamp to "stretch."

[Steve in SLO]

Agree with degreasing frame and seatpost and applying carbon paste. Also, make sure your binder bolt isn't bottoming out before the clamp grabs the post enough to prevent slippage. You may need a shorter binder bolt.

[dgauthier]

(. . .) there was no seatpost slipping (. . .) removed the seatpost to grease it up and now there is seatpost slippage (. . .)

So it was fine before you greased it? The same thing happened to me once. Cleaning the grease out of the clamp area fixed the problem completely.

Before trying any of the good advice here, try taking out the post and cleaning it with alcohol, and clean the inside of the clamp area of the seat tube too (that is, just the top 3/4 of an inch or so). That way the clamp area will stay clean and dry when you reinsert the post. The residual grease inside the rest of the seat tube should be enough to prevent seizing.

[seanile]

try another seat post. ive had two seatposts, same brand with the same number stamped on them, and only one fit the frame.
also, maybe file a little material away from the slot to make the gap wider.

[stien]

Grease the threads of the binding bolt. Perhaps the extra friction from corrosion is throwing you off.

[David Kirk]

Carbon paste even if nothing is carbon.

dave

[scharny]

If the outer diameter of the seat tube matches the inner diameter of an after-market seatpost collar/clamp, you could carefully cut the top of the seat tube off just below where the integrated clamp exists, clean up the edges of the cut, and then slide a new clamp over the top and be done with it.

I did this on a 1995 steel S-works mtb frame that had a situation where I had overtightened the integrated clamp too many times and the tightening braze-ons were touching.

[Lewis Moon]

What frame? I have been told that 27.2 on a really nicely built, silver soldered frame is really 27.4. My Waterford Paramount was like that.

[R3awak3n]

you guys are awesome.

Gonna try a different seatpost first since i have a few 27.2 seatposts just laying around. If that doesn't solve it, carbon paste it is.

[cinema]

i have the same problem. use carbon paste and tighten it down. then when you need to take the seat post out use a flathead or the body of an allen key between the ears and push them apart. it's steel it will move a fraction of a mm. if you can leave the object in there while you pull out the post. it will go back to being super tight when you take it out or cinch it down again.

[jtbadge]

+1 on carbon paste. Solved a similar problem on my alloy post/steel clamp.

[Dead Man]

Is it just me, or is it really hard to know how tight to clamp down the bolt on these brazed-on clamps? Always feels like I'm tightening way too tight, but the bolt still turns easily, so I feel compelled to crank on it more

Might be time to finally do a torque wrench

[R3awak3n]

Is it just me, or is it really hard to know how tight to clamp down the bolt on these brazed-on clamps? Always feels like I'm tightening way too tight, but the bolt still turns easily, so I feel compelled to crank on it more

Might be time to finally do a torque wrench

its not just you, even before it was slipping when I opened it up to re grease it felt like there was barely any torque on it.

[oldpotatoe]

This is a bit hard to explain but having seatpost slipping issues after removing the seatpost to grease it. The ears in the seatpost clamp were always very close to each other (frame was used, they almost touch) but there was no seatpost slipping so I ignored the issue. Just removed the seatpost to grease it up and now there is seatpost slippage. I do not want to tighten the bolt more since the clamp will touch each other and will not tighten more and afraid to mess things up more than they seem to be.

Wondering, is it possible I have the wrong seatpost? 27.2 chorus titanium, fits the frame perfectly, does not more around when its inserted, its not difficult to remove but not easy either, almost 100% the frame takes a 27.2.

Or should I shim? Maybe the seatpost is too thin? I never measured it but bought it as a 27.2 (don't think there was a 27 version of the titanium post).

Appreciate the help

Go to a decent bike shop that has a knurling tool, do that plus some carbon paste, it won't slip.

[R3awak3n]

Got home and switched seatposts. Was a Chorus TI and I now put a Chorus aero. Took it for a little ride and seems fine. The clamp ears don,t touch anymore, close to touching but there is still space and feels pretty tight. I measured both and they were close but I guess the aero has a mm more since it is definitely tighter.

Also I had used anti seize with the TI post (which I think was partly the culprit since that post didnt slip when it just had grease). Should be good now.

Thank you everybody