Does anybody have a sure fire way to stop seat tubes sliding down into the frame?

I have snapped one collar it was done up so tight ..and the tube is a tight fit in the frame so it isnt that its the wrong size (same with the collar it is the correct one) … drives me nuts the feeling the bike slowly getting smaller

cheers

carbon assembly paste worked quite well for me.

What size post do you have?

Have to confess that my immediate thought is "is the seat pin the right size for the frame?"

ragley/nukeproof do a 27.3mm seatpost now if that's any good…

Hope seat clamp – the new ones work a treat.

My XLight was like a involuntary gravity dropper

Have to confess that my immediate thought is "is the seat pin the right size for the frame?"

or could it be the seat clamp is the wrong size?

Been through this recently

Better Clamp ( Hope or Salsa) and even lightly sand the surface of the post (assuming it isnt't carbon) over the range where it clamps.

The seatpost is a 27.2 – fit is snug & frame manufacturer says it should be a 27.2 (both post and frame are new), the collar I'm not sure off hand but it was measured by micrometer before fitting & does take a gentle push to make it fit.

Its not just this bike I have always suffered with it, the collar I broke was a hope – I have gone onto bolt through rather than QR in case that helps.

Perhaps somebody somewhere is telling me to getting lighter.

I will give the carbon assembly paste a try (although frame and post are alloy). I have tended to use a secondary collar of gaffer tape which appears to work but cannot be the most elegant solution.

>Does anybody have a sure fire way to stop seat tubes sliding down into the frame,

Go up a size and have the sea tube reamed out by somebody that knows what they are doing

Toothpaste worked for me on my roadbike.

Toothpaste worked for me on my roadbike.

carbon paste worked for me with thomson tube in a steel frame, but it didn't half creak

carbon paste can help, but what cured my slipping was putting threadlock on my seat clamp bolt/threads as it seemed to be backing off from my initial tightening as if the threads where not a tight tolerance and once applied no more slipping

what make is it ?, some high end posts seem to be variable in stated size, I've had a lot of mither with this over the years, and found that overtightening the bolts just crushes the post at the point of contact,I now have a collection of Thompson posts that aren't much use unless I'm using a QR and therefore upping and downing the seat a lot and correct seat height is less important

I have found very fine lapping paste has always worked but can creak.

is the collar installed the right way round? I had no end of problems with a slipping post and couldnt clamp it tight enough. When I looked at it properly the clamp section wasnt over the slot and so not having the most effect.

spun it through 180deg and been fine ever since.

Had the same problem which was solved by degreasing and applying carbon paste. Magic stuff! The seatclamp does not even need to be tight now. It does creak quite a bit though.

I just had this on my Remedy. I cut up a coke can and used it to shim the seat tube by .2 of a mm. It's discreet and works like a dream

CArbon paste for both times i've had problems with this.

Silicone Sealant

I have recently had the same problem with thomson post and a P7 frame.
I tried the carbon paste stuff and I greased the seatpost clamp bolt.
I even phoned orange to check if it needed a shim or I wasn't damaging the frame.(Ididn't and wasn't)

In the end it was what jambo said… I had the seat post clamp the wrong way round……..
i.e. seatpost hinge next to slot on frame.
Doh.soft lad.

Carbon assembly paste

Then try a double bolt clamp as above

I also managed to snap a Hope QR so now use a Thomson non-QR

Its an on-one scandal and an easton ea70 post. I'm going to try the carbon assembly paste (not sure I am lookng forwards to the creaking though). Also I will try threadlock on the collar. The collar is the roght way round, I am liking the double nut seat collar – that may be in the next round of updates if the carbon assembly paste doesnt work.

Thanks for the suggestions

Toothpaste works almost as well as carbon assembly paste if you let it dry before riding. 🙂

Hmm I could of guessed it would be an on one!

I got so fed up with mine I bought a bike with an integrated seatpost. Perhaps a little excessive bnut it doesnt slip!