Seat tube crimp question

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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Have a gen 1 evo.

It has a crimp (fold in the carbon on the front side of the seattube opposite the slot) - this occured from originally using an MCFK clamp where the carbon between the two bolts got pinched and there is now a permanent crease - has been for years. Now using a smud clamp but the crease remains.

Anyway switched to a thinner diameter 0 setback post (carbonice) and notice it has been drawn into the crimp and itself has been crimped. I am looking at switching to a light setback post (deadalus most likely) and don't want it to get crimped/cracked - any idea how to fill in the crimp on the inside so the next seatpost can't get drawn into it. More worried about seatpost damage as the frame has been crimped for years without issue.

Cheers
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

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alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Interesting. Picture?

How deep is the crimp?

I'm surprised it didn't reduce the diameter of the seat tube. Are you sure you can even insert the new seatpost?

Is it a 27.2mm standard? What about using a cut down steel reducer insert and go with a smaller diameter seapost?

/a

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Yeah it is strange that the 27.2 seatpost installed easily. It first crimped with a ritchey superlogic installed which itself is unaffected by the crimp - likely as it is thicker carbon. Crimp in frame is probably 2-3mm. In post would be 1mm. Can post photos but not at home presently. Not interested in using a reducer as it will increase the weight over the superlogic (135g) even with a lighter 25.4 seatpost. (but actually not sure there are any lighter setback posts in this size)
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

sungod
Posts: 1702
Joined: Fri Dec 24, 2010 9:37 pm

by sungod

you could try filling with epoxy, maybe use a piece of old post coated with mould release to match the curvature

i'd be a bit wary though as it might create a 'wedge' that then gets driven into the post when tightened/under load

alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

What if you get another seat post clamp with only one opening and use it to try and flatten the crimp. It could be done during off season with another seatpost in the bike.

You could turn the clamp 45-90 degrees to avoid future crimps from developing. The pressure when riding should be mostly front/back.

This might sound crazy but if you have a slippery interface between seat tube and seat post you could try what I did. In order to help a weak seatpost clamp design and not overtorque it I put some loctite on the seatpost. First a tiny amount. After a month if it still comes out effortless then I know I can put a bit more. Be careful though.

Just brainstorming here..

/a

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