Wattsup

My beautiful, shiny Nitto post is slipping in my Titanium frame. I've tightened the Salsa clamp to the recommended 8nm, but it still slips a bit after a long gravel ride. I did apply a very thin layer of grease before inserting to prevent corrosion.

Should I use Carbon Assembly paste around the collar area to stop the slipping? What brand is best? Any other ideas? Won't silica embedded carbon paste get washed down in the bottom bracket?

What about using fine sandpaper on the post?

Iride01 

Absolutely certain the seatpost diameter's match? If there is no gap left in the clamp when it's tightened, then something is worn out or the wrong size.

Wattsup

Box that the post came in says 27.2, Salsa's specs say 27.2, and they is plenty of gap left in the clamp. Specs say to tighten the clamp to 8Nm. I actually tightened slightly more, maybe 8.5. The post still slipped 3 or 4mm. Maybe I should lube the clamp bolt?

Wildwood 

Lubing clamp bolt and overtightening should not be first option.

I would remove the lube and tighten as you did before, then ride. If that works, be sure to clean the post and top of seat tube at least annually, more often in wet and/or salty environ.

No info on paste for slippage.


Thanks for the reminder to go check & clean the seatposts on my CF and Ti bikes.

caloso

Coke can shim?

79pmooney

I would expect a Nitto post to be right on for diameter, but posts have been known to vary. So have seat tubes. I have also seen the slot in the seat lug/tube too narrow and come in contact, meaning all that extra work with clamp is doing nothing to clamp the post tighter.

I have aluminum posts in two ti bikes. Marine grease and standard (I think Salsa) clamps work just fine. I don't have a torque wrench but I do not use big allen keys and am not that strong. (If the slot is OK, you could get a spare clamp and over tighten this one. Break it on a ride and you should be able to limp home on the spare.

Ben

Bigbus

I think greasing the post might have been a mistake. Sanding it and reinstalling should do the trick or maybe even just cleaning the grease off really well if you're not comfortable taking sandpaper to it. If you do use sandpaper, use a light grade like 280 or 320 grit.

Iride01 

I had an old steel bike that gave me similar grief once. After puzzling for awhile I found that the slot in the seat tube had closed up completely even though the clamp had enough gap left.

I imagine it was from the softer steel getting thinner and expanding the circumference of the tube there. The seat post clamp had been seriously over tightened very many times. (back in the days when I believed everything should be tightened to just before the point of breakage.) Taking a file to the slot in the seat tube and making it a little wider solved the issue

Don't know if that could happen with titanium. Never worked with it myself.

JanMM

Sy Reene

I always used Park's SAC assembly compound with alloy seatpost in Ti frame. Because.. why not? Actually still use it with a CF post in the same bike also.

Wattsup

Yes, I have some of the stuff. I think I'll apply a small bit to post where it meets the collar. It's like a lightweight grease with bits of....well, the MSDS says glass and silica.


Hmm. Maybe I used the wrong grease. I used Park Polylube 1000. Maybe something thinner? I'm going to try the Park assembly stuff.

AndreyT

This ^^^^ is actually the crucial detail that must be clarified first. Until then this entire discussion is a pointless waste of time.

To the OP: When you tightened the seat collar, what happened to the slot in the seat tube? Did you still have the gap between the edges of that slot?

darkhorse75

Ive had the same problem with a Thomson post slipping in a titanium frame . If all else fails get one of these. Double seat post clamp

Steve B.

Wattsup

Plenty of gap left.

Sy Reene

What I'd like to see is Park come out with an Anti-Seize assembly compound.. not sure if such a think exists.. ie. a compound that prevents galvanic corrosion, but adds the grit bits for bite.

Wattsup

Here's the MSDS of their anti-seize. What's the talc, limestone and silica for?


https://www.parktool.com/assets/doc/.../ASC-1_SDS.pdf

Sy Reene

Not sure.. but it wouldn't be too gritty if it's supposed to help lubricate for threads in various usages. I'm purely guessing, but perhaps at least the talc and lime help act as electrical barrier material between the 2 dissimilar metals to help prevent galvanic corrosion which ASC is supposed to do.

Wattsup

Used the SAC compound today....worked great, no slippage after 2 hours of riding gravel!

MikeyMK

Stainless or copper engineers shim, equally thin, on clean dry components.

Koyote

Lots of good advice here. One more possibility: use calipers to check the seatpost diameter - make sure it is actually 27.2mm.

Shimagnolo

I have a bike with a CF frame that had seatpost slipping in spite of being tightened to the mfgr's torque max.
I tried Tacx carbon paste, but it still slipped.
So I went to one of these: https://www.ebay.com/itm/Gineyea-Sea...-/273719267198
It is an interesting design;
The upper half clamps onto the post, (not the frame), and controls the height.
The lower half just keeps the post from rotating, so it needs very little clamping force on the frame.
It works perfectly.

biker222

fietsbob

I have 2 bikes I doubled up the clamps 2nd one goes on top of the frame seat post clamp, and grips the seat post directly

QR for both on the Brompton, the other bike a 27.2 clamp one of these, on the other ..

fietsbob

here is another.. from SJS


The main clamp not welded on part of the frame , but a separate band, of course..
& a 31.8/1.25" OD seat tube.. 27.2 seat post..


....