Hey, had a look down the seat tube on my Carbonda 696. Seems there is some carbon fraying near the UDH. My guess is its from when they drilled room for the UDH bolts. Should I be concerned about it, or is that normal? See pictures

Could also be bladder residue from molding process I think

There tend to be "fraying" burrs and rough sheet edges on the inside of Carbonda frames; it's 99.99% aesthetic rather than structural. They're more perfectionistic for their branded frame production (Nukeproof et al) but probably skip that for their in-house designs to save employees' time.

If I had to guess — it's tough to tell from the pictures — this isn't anything worth worrying about unless it's markedly different from how the frame was when new. And maybe even then, since edges that stick out from the resin could relax over time from the shaking and flex of riding but have no effect on the rest of the carbon which is firmly embedded in the resin matrix.

The first picture definitely looks like more loose fine slips of material than I've seen but it's tough to judge scale here... however I would guess that this is just a particularly unaesthetic detail that still isn't structural. As long as the frayed pieces aren't coming loose or rattling against the tube walls I would assume they'll never affect you.

Thanks for the feedback. The frame is new, so judging by your responses I guess this is mostly aesthetics as you say 

Is it from where the hole for the lower bottle cage rivnut was drilled? Also, looking down the seat tube gives a view of the bottom bracket, not the derailleur hanger; that can be seen by looking from the bottom bracket back towards the driveside chainstay. Generally not visible without an endoscope.

Quote from: frnchy on May 01, 2025, 01:09:06 PM
Is it from where the hole for the lower bottle cage rivnut was drilled? Also, looking down the seat tube gives a view of the bottom bracket, not the derailleur hanger; that can be seen by looking from the bottom bracket back towards the driveside chainstay. Generally not visible without an endoscope.

Could very well be since they are so close apart! Just in that general area