I am planning to get a second hand medium range road bike and this is the first full carbon road bike I'm getting. However, upon checking the bike, I can see there is a surface chipping on the top tube of the frame.
This seems to be caused by a claw bike stand and seems surface only. I cannot see any carbon fiber strands popping up as well. But bit worried as the carbon frame repairs can be high. So your expertise would help me a lot to make a decision.
The damaged area initially appears large and shallow and within the clearcoat only but there are clearly scratches into the first layer of resin. We can't see any trace of loose fibres yet, or they're obscured.
One of the clearcoat's jobs is moisture protection; to shed rain and sweat to keep the underlying layers clean. That layer has been breached.
I'd worry that if the PO took that much care with the paint/frame, where else have they taken minimal care?
Ultimately, its up to you and your tolerance for risk and costs.
I'd buy it if the price was low and the fit was good. However if the cost is more than 10-20% of a new bike, I'd have to think hard about expected mileage/lifespan vs other options.
Bike availability comes into it too - if it was a 60cm frame or larger I'd be more-accepting of other issues because they're uncommon.
A brand new bike will last 10 years minimum and likely double, and won't have damaged carbon to begin with.
Remember, there's always more bikes out there. And the consequence of the top tube failing during a ride are significant.
A possibly relevant answer is here, in which I advocate that if it's clearly damage to just the clearcoat, leave it, else exercise watchful waiting unless you can see broken fibers.
You mention that it looks like the frame has been clamped in the area in question. Frame tubes are not designed to withstand clamping forces. Yes, it is possible to design carbon structures that can take clamping loads, like seatposts and steerer tubes. Frame tubes aren't designed this way. If you actually have information that someone clamped the bike in a stand, then I would avoid buying it. I don't know how likely it is for a carbon bike to take fatal damage from being clamped, but it is something you can't rule out and it's definitely something that mechanics know not to do.
Alternatively, your offer price could take into account the probability that the frame is damaged and will need repair, but then the seller may not accept it.
