Slipping seatpost

[gxaustin]

Brucey
Your photo was the ideal solution where the clamp is small, neat and can be used to mark the position of the seat post height where it has to be removed regularly (nicer than tape). I'm sure they exist but searches for seat post/pillar clamp or 27.2 I.D clamp just bring up the usual seat post clamps. I've found a neater looking double clamp at Ribble.

[De Sisti]

Brucey
I've found a neater looking double clamp at Ribble.

Link please.

[CREPELLO]

Someone up thread mentioned carbon anti slip compound. I'm interested to know why this possible fix (for a few £) wouldn't be a quick solution. Is it because it wouldn't have the water proofing properties of grease, or just appear incompatible with it? Grease does seem a bit counter-intuitive an application here, with it's lubricating properties. What's really needed is something which is both a friction compound and one which reduces corrosion and water ingress. Perhaps mix the two together.

[CREPELLO]

I should also mention my own epoxy putty fix that I used a while back on an oversized seat tube. Well, I put a skim of it on the seat post, then sanded it back till the post fitted the seat tube. It may have been a bodge, but it worked.

[gxaustin]

I should also mention my own epoxy putty fix that I used a while back on an oversized seat tube. Well, I put a skim of it on the seat post, then sanded it back till the post fitted the seat tube. It may have been a bodge, but it worked.

I hadn't thought of that. I used a bit of beer can on my old Falcon. The old original seatpost was marked 26.4 and measured 26.2mm causing the clamp to distort more than I wanted. Accordingly I bought one for 26.6 - annoyingly it measured 26.6. So I bought another 26.4 - it measured 26.2 - hence the beer can

[gxaustin]

gxaustin wrote:
Brucey
I've found a neater looking double clamp at Ribble.

Link please.

https://www.ribblecycles.co.uk/ribble-s ... -twin-bolt

[pwa]

gxaustin wrote:
Brucey
I've found a neater looking double clamp at Ribble.

Link please.

https://www.ribblecycles.co.uk/ribble-s ... -twin-bolt

Seems like a good idea, but you'd need to make sure you stick to the low torque figure on the top bolt. Potential for disaster in the wrong hands.

[gxaustin]

That's a low figure!

I'll get my torque wrench out and take great care, thanks.

[Samuel D]

These double-clamp models don’t seem to fit the Spa Audax, which has a 30 mm seat tube and 27.2 mm seatpost. Has anyone found one that would work with that? I suppose black is on the only tolerable colour for this.

My problem has got steadily worse (slips more) the more I’ve cleaned and fiddle with the clamp. Highly annoying.

[gregoryoftours]

These double-clamp models don’t seem to fit the Spa Audax, which has a 30 mm seat tube and 27.2 mm seatpost. Has anyone found one that would work with that? I suppose black is on the only tolerable colour for this.

My problem has got steadily worse (slips more) the more I’ve cleaned and fiddle with the clamp. Highly annoying.

I can still send you one of the clamps I have if you don't find any better solution

[horizon]

I've now swapped the clamp on my Dahon onto the Tern. Miracle cure! The Tern is two years old and not overly used and has had the problem from new. The difference between the two bikes was striking - one a light touch to secure, the other a constant struggle.

I've looked at two possible reasons:

1. The rack made it difficult to position the closing clamps over the slot in the seat tube. I don't know if this makes a difference. The Dahon clamp is slightly different and will allow this.
2. I've looked at the Tern clamp in the hand and it appears that the two clamp faces aren't parallel and don't meet face to face at the extreme closure: I've discounted this as they are OK when not at extreme closure so I am presuming it is normal.

UPDATE: I've now tried the Tern clamp on the Dahon and even at maximum closure it won't hold the seatpost at all so it is either oversize or badly made (and therefore oversize).

[Brucey]

These double-clamp models don’t seem to fit the Spa Audax, which has a 30 mm seat tube and 27.2 mm seatpost. Has anyone found one that would work with that? I suppose black is on the only tolerable colour for this.

My problem has got steadily worse (slips more) the more I’ve cleaned and fiddle with the clamp. Highly annoying.

IIRC the closest size is meant to fit a slightly larger seat tube. I'd (in a heartbeat) buy one of those and fit a shim between it and the seat tube.

cheers

[horizon]

Samuel D wrote: Does the panel think I should try another clamp before taking more extreme measures?

Did you change the clamp in the end? It worked for me.

A couple of other points:

1. Being a folder, the seatpost isn't greased for obvious reasons.
2. Being a folder, I'm not sure an external shim would work as it might slip at each folding (there might be a fix here but a new clamp is better).
3. Being a folder, there might be fewer options for clamps Edit to add that it's a 40.8

[Samuel D]

I got a 30.0 mm Salsa Lip-Lock. It looks pretty good although it doesn’t have a curved washer on the bolt-head side. Neatly made and fitted nicely. I greased everything (seatpost included one more time) and torqued the clamp bolt to the specified 8 Nm by torque wrench. I’ve only done two rides totalling 110 km since then, but so far it has held in place. A bigger test will come this weekend when I’ll do a longer ride on rougher roads. Before I go, I’ll put some masking tape on the seatpost just above the clamp to make sure I perceive any drop that happens. Fingers crossed.

[niloc]

Would a 30mm Surly Constrictor clamp be suitable to stop an anodised 27.2mm seatpost slipping down a steel 29.8mm OD (27.2mm ID) seat tube. Or would a mix of grease and gripper paste be better. Or should I abrade the anodised finish? Or any other recommendations please?