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Discussion Starter · #1 · (Edited)
Hello,

I just got my Look 565 frame. I bought it used on ebay and I think I have a real problem with it.

My Thomson Masterpiece has a 27.2mm diameter and the Look frame does so as well. As I put my seatpost into the frame, well deeper than the minimum insert, I can move it back and forth. The seat tube diameter changes as soon as I am under the aluminum lugs. Now if I tighten the seatcollar, the seatpost is only fixed there and a little deeper nothing.

Putting my finger into the seat tube I can feel the border from aluminum lug to carbon tube and there is something like a 1mm difference in the diameter, where the seatpost isn't fixed. A lot more deeper there is another border where the tube gets tighter again. Is that normal? I can't really use the bike if the seatpost is only fixed at the top and moves around a bit deeper into the seat tube.

Any suggestions? I measured my seatpost and it's anywhere 27.2mm and I am pretty sure the problem lies in the frame.

KJ.

edit: I just took 2 pics of it. The first border is where the aluminum lug ends. The second I can't explain. It is not all around the seat tube but only at around half of it. Could it be that the carbon is damaged and if that's so, why isn't the painting on the outside?





Another thing I just got to see is where the seat tube ends, and the aluminum lug begins on the BB there is a crack in the color? Is that normal? I mean there should be some slight movement in this area which could cause the painting to crack.

 

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First, the "crack" you see at the base of the seat tube is normal. It's where the carbon tube is joined to the aluminum bottom bracket. It's just a slight difference in diameter. More of a "ridge" in the paint than a crack, I would guess. It's on my 565, too. You can feel it with a fingernail, altho you can't see it on my frame because it's painted black in that area.

As to the seatpost fit, I'd suggest trying it for a while built up. You don't really say if you can feel flex in the seatpost. I can't feel any in mine (with a Look Ergopost), but I know there is some flex in that area because after three or four years use the clear coat is showing some slight peeling around the top tube lug joint just ahead of the seatpost and seat tube. There's no cracking in the tubing or joint.... Just a slight bit of peeling of the clearcoat at the joint on my bike. I am pretty certain this is jus the result of some flex and simply normal wear and tear on a painted carbon frame. The frame is designed to have some flex and the paint on top of it likely doesn't give as much. Maybe sometime I'll have the clearcoat redone in that area, or just keep riding and enjoying the bike. I'm really not worried about it.

If the post fits poorly, double check its size with a micrometer. Or swap it out for another post. I've never used a Tompson, so can't really comment about it.

Is the lug holding the seatpost aluminum? I don't think it is on my bike... I think it's carbon, too. Anyway I used carbon assembly paste on my carbon post when I put it together. Get a tube of the stuff at your local bike shop (about $6) and it will probably last a lifetime unless you start building CF bikes for a living.

I do recommend getting a Campy style seat clamp, if the frame didn't include the original clamp from Look. See this current auction as an example. Notice the way the slot is offset and clamped at an angle? I think this is safer to use on carbon tubing. A squarely slotted clamp can gouge and even crush a carbon tube.
 

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I read this twice and don't understand the seat lug problem. Except for steel bikes, 27.2 frames generally use some sort of insert to narrow the seat lug down to 27.2. That insert is generally an inch or two long, then it ends.

What is your frame failing to do?
 
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