Carbon diagnosis

[rbtmcardle]

Any thoughts on whether this is a cracked tube or simply paint damage.

The frame was new and built once with di2 by a qualified and trusted mechanic at my lbs.

Meivici seat tube.

[gone]

Hard to tell but looks cracked to me. If the derailleur clamp was tightened enough to compress the paint, which is what appears to have happened judging from the picture, it was pretty darned tight.

[Lionel]

You need to remove the paint to find out.

[RedRider]

There was a good amount of paint on those MeiVici frames and that location has some of the thickest tubing. The torque from an electric FD is greater than mechanical. Campy Record FD clamps were particularly sharp and Parlee carbon ones worse.
Hope it's just the paint...

[texbike]

I have a friend that has a carbon Serotta that ended up being cracked in that same area from over-tightening the derailleur clamp.

Texbike

[Louis]

I'm guessing that's more likely to be a structural issue than just a cosmetic paint issue. The fact that the whole area is showing signs of distortion does not bode well.

Take some tape and mask off the area, sand it down (carefully) and see what's going on.

Good Luck

[Peter P.]

Here's one way to tell if it's cracked-

Take a small, clean, white rag and stuff it down the seat tube with a coat hanger. You should be able to retrieve it later by putting a barb or hook on the end of the coat hanger.

If you're lucky, that area of the seat tube is accessible from the bottom bracket.

Anyway, after stuffing the rag down the seat tube to the location of the clamp,
lay the frame so the seat tube is horizontal and spray the outside of the area with a colored fluid like Liquid Wrench or machinist's layout dye. Spray it several times so you're sure the area is saturated. Let it sit for a couple hours.

Remove the rag and see if there are any telltale signs the fluid penetrated the crack and reached the rag.

I used a similar method to unearth a crack on my steel frame.

Edit: If you DO have access to the seat tube from the bottom bracket, then lay the frame so the seat tube is horizontal. Place a piece of cellophane tape on the outside of the tube over the suspected crack. Then flow a puddle of Liquid Wrench or whatever into the seat tube and let it sit for an hour. If the crack is real, the liquid will migrate through the tube and stick to the tape.

[gone]

Great idea Peter P! I'm going to have to remember that one. Much less destructive than sanding.

[RedRider]

Originally Posted by texbike

I have a friend that has a carbon Serotta that ended up being cracked in that same area from over-tightening the derailleur clamp.

Texbike

Yes, that's a problem caused by lack of the correct torque wrench setting. I can attest to the Serotta staff taking details like these very seriously. Every dealer had a list of recommended torque settings for everything on a frame. Customer Service also had the list so if anyone called with a torque question it could be answered immediately.
If a Meivici seat tube cracked from over tightening the FD someone really had to muscle it.
Unfortunately, there's no good remedy to a damaged Meivici carbon tube. The only safe solution would be to replace it but those tubes are no longer available. Patching a repair would not be an option I recommend.

[rbtmcardle]

Thanks all for the insight.. the irony is that I received this frame new from serotta after I sent mine back to be repainted... when they received it (original) back I was told my "old" frame was cracked at this same spot.. so this may be the second frame with the same issue. I gave up wrenching on my own a few years ago.. and I really trust the mechanic.. very frustrating.. I will try the soak the area trick and move forward from there.. at the very least get a parlee clamp.

[Dead Man]

I had a carbon steerer that looked a lot like that, from an over-tightened stem, but worse.. the carbon itself was obviously crushed. No paint to offer doubt. Looked perfectly clean on the inside- plug slid in and out with no hangup, couldn't feel anything with your finger. I doubt liquid would have soaked all the way through, as I suspect only the top layers of laminate were crushed.

You'd never know until your face was bouncing off the busted jagged edge of broken steerer, or you just happened to be replacing your stem (this case).

[nicrump]

read this thread. it applies more to your situation than the steerer.

http://forums.thepaceline.net/showth...ighlight=creep

[Louis]

Originally Posted by nicrump

read this thread. it applies more to your situation than the steerer.

If it is creep, might this location be less critical than on a steerer tube, given that an F-der probably doesn't apply huge loads to that area?

I'd think that if it's just due to deformation of the composite and isn't an actual failure, then at that location it might be OK to ride.

[ultraman6970]

The bike creaks?? a crack in that area should creak IMO.

[nicrump]

if it were before me i'd do a tap test. if it had tonal change(even loose paint can cause this) i'd sand away the finish and tap again. if tonal changes, pass it on to a pro to fix.

the crux of it is the damage site, if you wanna continue a band clamp fd then the fix should maintain round and correct O.D. all while actually fixing the problem. not impossible.