Tomm Willians

I’m looking at a frame for sale locally where the previous owner shortened the carbon seat tube. He retained the cut section and the cut seems to be well done and square. Is there a method/product which it can be securely re-attached ?

Steve B.

Calfee is the company to ask as they do a lot of carbon repair, but I doubt they'd be able to re-attach a severed section of straight tubing. It sounds like the frame is too small for you if you are considering this.

Crankycrank

Photos, brand, year and model of bike would be helpful. As mentioned it could probably be reliably re-attached by a good CF shop and I'm assuming it's an integrated seatpost and not round? Not cheap to get it done so get some estimates before considering buying the bike. If it is integrated and needs a proprietary seat clamp I would stay away since if the clamp were ever to break you may not be able to find another.

Iride01 

Giant TCR? If your legs are longer than the original owner and outside the range of what's left, then that isn't the bike for you.

But if the owner is giving a huge deal on the bike, then check with some of the places that do carbon fiber bike repair. Seat tube above the stays and top tube probably takes a lot of different forces. I'd not be inclined to want to repair that myself, though I might do a DIY repair of a top tube, down tube or even a stay.

Tomm Willians

It is a 2006? Wilier Imperiale with a seat post and clamp like this one.

CliffordK

Oh, some kind of a seatpost mast... where all the adjustment is in the mast?

There are likely two ways to repair it.

Pretty.... or Functional.

I'd probably cut a wide V-Groove all around the joint. Then wrap with carbon fiber and epoxy. Then follow up with wrapping an epoxying 2" or 3" additional of the mast.

Somewhat like what you see with the construction of a bamboo frame.



Multiple layers, thicker in the middle where the joint was.

It isn't a repair I would take lightly.

Tomm Willians

Would it offer any additional strength if i filled the inside of the post say about two inches above and below the cut with an epoxy resin to form an internal “block” so to speak ?

Unca_Sam

Until a carbon fiber repair expert chimes in, this isn't really the place to go asking for assistance in mending a cut-down safety-critical component like a seatpost. The earlier advice about getting repair quotes or looking for a replacement mast is the best advice you'll get.

CliffordK

I wouldn't fill with a solid block of resin. But that is a good point that if you have adequate access, you might be able to work from the inside (or both the inside and outside). There are carbon fiber expandable sleeves that could be used.

You'd need something that can give you pressure. Perhaps a GAADI bicycle tube, although you might be able to find CF specific pressure tubes.

squirtdad

best option is to find out if you can get a replacement and if you can figure that into what you will pay for the bike otherwise any fix is going to be a kludge, at risk of failure with resultant risk to health, and probably would not ride well

the fact that calfee will not repair seat posts should be a fair warning to anyone trying to do a repair

https://calfeedesign.com/carbon-repair-faq/

What we will not repair

Rejected repairs include: aluminum-to-carbon bonding, carbon handlebars, forks, seat posts/integrated seat posts, stems, damage to carbon wheels, and metal frames.

Iride01 

I wouldn't fill it solid with resin. Especially not just a small section. You might be changing the natural flexing of the tube in a way that will cause stress points and issues later. But then again maybe not. And if you filled the whole thing, then you'd be getting rid of the flex that is supposed to be giving you a more comfortable ride.

That's why you need to ask someone in the business of repairing carbon bikes. Whether you actually use them or not, they'll provide you with information from a source you should be able to trust. And maybe they'll even tell you what they'd do and you can just DIY it from there if that's your thing.

CliffordK

Beyond Calfee, there is also Ruckus Composites in Portland Oregon that specializes in CF repairs. Perhaps others too.

squirtdad

they don't have a similar FAQ but no mention of seat posts in their we repair it all label,

We Repair it All

Top Tubes - Head Tubes - Bottom Brackets - Seat Stays - Chainstays - Downtubes - Dropouts

Tomm Willians

I also contacted Ritchie to see if they make a taller clamp

Tomm Willians

Ritchie does not make a taller clamp but I just found these for conversion to a round post. I assume they would have to be glued in somehow?