Best material for a shim for seat post?

[531colin]

There are 2 bolt seatpost clamps where the top bolt nips the clip up on the post and the bottom bolt nips up on the frame; neater than a Jubilee clamp?
Google finds them as “2 bolt seatpost clamp “
No personal experience but I must have read about them on here, somebody will know!

[PT1029]

“2 bolt seatpost clamp “ I have one, came as standard with my Landescape tandem frame. In my case, it is to stop the (hopefully) strong riding stoker from swivelling the rear handle bars/front seat post round.
Never had the sinking seat post issue on any bike except once or twice when I had not done the clamp up tight enough.

[Brucey]

beverage cans come in steel or aluminium types and are slightly different thicknesses as a consequence.

[Keezx]

There are 2 bolt seatpost clamps where the top bolt nips the clip up on the post and the bottom bolt nips up on the frame; neater than a Jubilee clamp?
Google finds them as “2 bolt seatpost clamp “
No personal experience but I must have read about them on here, somebody will know!

I've used such a thing for years on my titanium frame which had a titanium sleeve and my carbon seat post kept slipping until i fitted the double clamp .
Worked perfectly until I found out I could replace the titanium sleeve by a similar alloy one and never had problems since then.
Definately recommendable in difficult configurations..

[531colin]

There are 2 bolt seatpost clamps where the top bolt nips the clip up on the post and the bottom bolt nips up on the frame; neater than a Jubilee clamp?
Google finds them as “2 bolt seatpost clamp “
No personal experience but I must have read about them on here, somebody will know!

I've used such a thing for years on my titanium frame which had a titanium sleeve and my alloy seat post kept slipping until i fitted the double clamp .
Worked perfectly until I found out I could replace the titanium sleeve by a similar alloy one and never had problems since then.
Definately recommendable in difficult configurations..

That’s interesting; I’ve had one titanium frame with a titanium sleeve which is still an inveterate seatpost slipper and 2 which have never slipped. But in my frames the titanium sleeve has been fixed. (Well, I think so!)
Could you work out if the difference was due to material or dimensions of the sleeve?

[Keezx]

It was definately the material responsable for the slipping post.
Diameter of the titanium sleeve was spot-on , but the inner surface was too smooth.
My first impression was that the sleeve was welded in the seat tube, but it turned out ( after 2 or 3 years), that is was only pressed in and I could buy a similar aluminium alloy sleev to replace it.

[Brucey]

.......Diameter of the titanium sleeve was spot-on , but the inner surface was too smooth........

how did you measure it? I have never seen a moving seatpost that did not also wobble, and Ti would be the last material I'd expect problems with.

[Galactic]

Shim is in. Didn't have a drinks can, shops are nowhere nearby and I didn't want to wait, so I cut up an olive can that was made of a thicker gauge alloy. It was a bit of a struggle to get it in with the seat post, but it's there now, and the seat post can still be moved around with the collar undone.

Quick test trip of half an hour over uneven ground and the post hasn't shifted at all. So job's a gudden and I'm a happy bunny.

Thanks for the suggestions, I'm sure there'll be a few more coming, and I've noted a few of the ideas for future use.

[Jdsk]

Well done. Thanks for adding the outcome.

Happy Christmas

Jonathan

PS: As it's this forum... black or green olives? ; - )

[Galactic]

PS: As it's this forum... black or green olives? ; - )

Since you ask ... it was actually a tin of dolmades. But I thought that might be a little too esoteric and difficult to imagine the material it was made of (even for this forum of globepedallers ), and the metal is the same as the tin of the stuffed green olives that I didn't use

ETA agh! Just realized, it wasn't even dolmades, but gigantes beans

[Jdsk]

: - )

Jonathan

[Brucey]

if the shim is short, the chances are that you needed to do both things to solve the problem anyway.

[Galactic]

if the shim is short, the chances are that you needed to do both things to solve the problem anyway.

That thought did strike me as I was fitting the tin shim. It's a little on the short side, but I consoled myself with the thought that the distortion would nicely hold the bottom of the post, at least until I get to the shops in the new year for a drinks can shim

[Brucey]

most 'other tin cans' are a little bit thicker than beverage can. IME if you got such a shim in at all, probably it means the gap is a bit large, very possibly larger than would be usual for a single layer beverage can shim, anyway

[Galactic]

most 'other tin cans' are a little bit thicker than beverage can. IME if you got such a shim in at all, probably it means the gap is a bit large, very possibly larger than would be usual for a single layer beverage can shim, anyway

The tin can shim is now in, so there's no immediate rush to change anything, but what you wrote did get me wondering whether I could use a drinks can shim doubled up (ie wrapped around twice, or one-and-a-half times or whatever)?

I note that manufactured shims have a slit that I've always conscientiously aligned with the slit at the top of the seat tube, and I've done the same with the gap in the tin can shin I've just installed. But provided the shim material is tightly wrapped around the seat post, would it still need a slit/gap?