for the carbon specialists

[jenk]

Hey all

for all thise in the know that are carbon specialists please swing your knowledge here

My friend came over today very distressed about his bike, he pointed to the top tube when i asked what is wrong, he told me "the wind blew a ceramic pot off the shelf and it landed on his bike, the worst part was he was heading to move it as it occured, thus he saw it happen, poor bastard. I do feel for him but I am reaching out to my fellow weenies to ask the following:

I noticed a small hairline crack in the top tube, the carbon in that area feels margainally weaker than the rest of the top tube, My questions are is it safe for him to ride and is it worth trying to repair if not safe? also is it a hard fix or should i tell him all of the bad news?


many thanks all

[warthog101]

The potential is there for further unseen damage.
It would be safer to have it inspected by a carbon repair specialist imo.
I am no carbon expert however.

[jenk]

That is ecxactky what i advised, its sad an unfortunate but still he wants to know if it is rideable still.

[tjvirden]

Hey all
[...snip....]
I noticed a small hairline crack in the top tube, the carbon in that area feels margainally weaker than the rest of the top tube, My questions are is it safe for him to ride and is it worth trying to repair if not safe? also is it a hard fix or should i tell him all of the bad news?


many thanks all

Based on that, yes it will be safe to ride.

For a competent repairer it is a straightforward fix, but will be expensive if done to a high cosmetic standard (depending on the finish/graphics).

Edit: I'll add that there is always "unseen" damage from that type of impact (shear failure between layers, aka delamination), but the nature of carbon and stresses on the top tube mean that there's essentially no possibility for the damage to spread on its own.

[wheelsONfire]

What frameset is it?

[hannawald]

If you see a crack on the spot where the accident happened, it is quite obvious you have to find a carbon repair specialist and stop riding the bike.
Should be repairable so you don't recognise that it has been repaired. But you will need to disassamble to bike and it will cost something. I don't know the prices in your country, but if it is not an old bike than worth it...

[sylvain70]

Painting is usually a good clue that the composite is affected. I repaired a superSIX in the past that had a little crack of painting. It was not linked to a crach or impact. After sanding it a little bit, I discovered wrinkles of carbon fabric. The layup was not good and it generated very small delamination... But difficult to say if it is ridable or not.

I think you should keep an eye on the crack, if it moves or not. If it moves, even a little bit, repair the frame. It is easy (Painting is not easy )

[Kimmoth]

99.9% sure it's safe to ride, but maybe a 15% chance riding it would enlarge the damaged area I'd guess