Had this a few times now….. is there a cure ???
what have others done….?

I swapped the seat clamp for a cheap brand-x one from CRC.

if it is shiny black it will stop when the black stuff wears off.
Hope qr by any chance?

is your seat clamp Hope by any chance. i have had this with several hope seatclamps and once swapped for something that you can actually tighten the seatpost doesnt move!

Works for me

carbon grip stopped mine, thomson post ally frame

not a hope seat clamp but a gt clamp
as it happens the hope clamp on my other bike is great no probs at all 😕

Salsa clamps are the only ones that work for me.

mine was (is) a hope

Had an Avalanche with the same problem last week, was able to fit a 27.4 post in the frame so it was obviously a bit loose to be gripping properly, also found the plastic bushing in the GT qr had worn away leading to extra lever friction when trying to clamp.

does the carbon stuff work in steel frames ? ( my Thomson post is a bit prone to slipping, not on a qr, bolt up, but I have to set the bolt so tight I worry about stripping it)

I had the same prob, changed to a Spank seat clamp and no more slipping.

http://www.effettomariposa.com/carbogrip_en.html
Effeto claim that:
It is basically a special high-molecular weight silicone resin that, sprayed on a bicycle part before assembling it, polymerizes (in a time ranging from 3 to 5 minutes) into a grippy surface with the following characteristics:
prevents part slippage and the dangerous, normal reaction when a seatpost or handlebar slip at the recommended torque value: overtorqueing the bolts!

I had it with the terrible Bontrager clamp that came on my Trek 8k, and then with the Hope QR that I replaced it with – now I have a Hope Bolt Clamp and it doesn't slip at all. I get the impression that the Hope bolted clamp could crush the seattube and the seatpost if I kept tightening it.

so whats the thoughts on whether the carbon stuff will work with a Thomson post in a steel frame ? I can't see why not, but don't want to splash a tenner if it won't…

cheers

The carbon grease made mine a little better(thomson in ally with hope qr), changing from hope qr to hope non qr solved it.

Thomson seat post is my cure. I bought a second hand singlespeed the other year with one and it was great. Now I have a Thomson on every bike, as other seatposts just slip or bend.

With a Thomson in my hardtail I rode 5 days with a big rucksack and a seatpost mount rack across the Cairngorms and the post didn't move a mm. Literally, as I had marked it with a pen at the idea height. Don't need to do up the clamp so tight you have to knock it open again with a large rock, either.

A tiny bit of grease in the frame when it's new and then immediately wipe it all out again.

just applied some carbon grease, so will see how it goes. post certainly felt tighter going in and the bolt was creaking when nipping up, so here's hoping -)

(Thomson post in steel frame with bolt up clamp)

Unlike Scootash, the Thomson I had just would not stay in the right place and I was glad to see the back of it. The Ritchey one I have now is fine now the gloss finish has worn off.