martslc

What does this mean?: "frame had a core shot to the carbon fiber"

See: Bicycles: Road Bikes Classifieds for Utah, Idaho, and Wyoming | ksl.com

DiabloScott

It appears to mean structural damage.

CliffordK

The seller has circled in red a scattering of little cracks in a circular pattern in the top tube.



The frame likely took a significant blow at that point. History of what happened might help determine if there is damage elsewhere on the frame.

There are professional frame repair services, but they are not cheap.

For example Calfee

It would seem like that would be a place where you could reinforce with an external ball of Carbon Fiber cloth, but it would leave a visible repair.

AnkleWork

It means it is not worth the asking price . . . probably not worth anything.

gsa103

That's a steep price for what looks like wall art.

Realistically, you're looking at something in the neighborhood of ~$400 for a repair+paint (since you'll probably need the tube wrapped).
Pricing « Carbon Fiber Bike Frame Repair

That brings the effective price up to ~$700-800 for a basic Evo frame (which is about what they sell for on ebay). If you can get it for $200 or less, maybe it's worth dealing with, otherwise I'd pass. The other option is if you're comfortable with your own repair work, in which case, buy it for ~$250, and ride the hell out of it.

DiabloScott

It'd probably be OK as-is on a stationary trainer.

TGT1

"core shot" is a colloquialism borrowed from rock climbing.

Climbing ropes are constructed with parallel fibers overlapped with a woven sheath. The internal fibers provide most of the strength and the outer weave protects them. (Kern-Core, Mantle-Sheath = Kernmantle rope)

A "core shot" means that the internal fibers are damaged and one more fall on that rope is gonna kill ya!

Reynolds 

Forget it martslc, it's Carbon.

OnyxTiger

Personally, I'd take up to watching some YouTube vids of CF repair, get the necessary tools, and get to work on it. There's a company that does professional repair on frames that has a tutorial of how to fix these things... it really doesn't look all that difficult. That might be what I'd do if anything bad happened to my frame. I figure if I mess it up any worse, then I'll pay for someone else to do it over. But if I get it right?... well, then I just found a new life skill set.

CliffordK

Ahh, the ever authoritative YouTube.

But, yes, it would be a fun project. Prices are all over the place on the Cannondale EVO frames. So, say a $400 repair, one might save a bit over an undamaged frame, but a repaired frame will at least affect the resale value.

If you could get it a bit cheaper, perhaps one could take it on as a personal project. Say your $200 Cannondale

martslc

The only thing I would be hesitant on is you do get it wrong how you going to know until it possibly gives way on you.

Zef

Could also be a colloquialism borrowed from Skiing where it means the ski hit something that caused damage through the base material down to the core of the ski.

TGT1

The climbers probably got it from the skiers. Lot's of overlap there.

In in either case it means a piece of equipment with concealed damage that, if you depend on it, you might produce a catastrophic outcome.

Brad M

A core shot rope is one where the sheath is damaged to the point of exposing the core, not hidden damage to the core (which in normal use is very unlikely to happen.) Calling this frame core shot is not accurate as the carbon fibre is not exposed.

mconlonx

Zef

To be accurate:
with regards to climbing rope - a core shot is damage to the rope where the damage has affected both the core and the sheath of the rope so that the damaged core is visible OR damage only to the core of the rope (not visible due to an intact outer sheath) but can be felt through the sheath of the rope.

in skiing a core shot is damage to the base of the ski where he ski is scratched or otherwise gouged through the plastic base down to or into the core material of the ski. This type of damage is by no means concealed and is very apparent on visual inspection.

With regards to the photos above of the bike in question...there is apparent damage as indicated by the cracked paint. The degree and depth of the damage is unknown and without more info to further ascertain what happened or how the seller is using the term "core shot", one could/should consider the condition of the frame suspect.

Buy at your own risk.

-j

CliftonGK1

If you *think* you got it right and it fails underneath you at 35mph, you've found out why you pay a professional to do things properly.
But there's probably a YouTube video on how to perform dental replacements, so you'll be fine.

CliffordK

The top tube should be the easiest to monitor for failure of the repair, and I would think also the least likely to cause a sudden catastrophic failure.

The big question is whether it would be best to grind out damaged material and attempt to do a hidden repair, vs simply layering a few extra layers of carbon on top which would then lead to a strong, but visible repair.

fietsbob

Only get it to strip the components off. then saw up the frame and toss it in the bin.

Spaghetti Legs 

It means "my wife is fed up with all the time I spend on my bike and she hit it with a baseball bat"

martslc

Amen brother!

OnyxTiger

Possibly. Same could be said about professional third party companies and their work... or original manufacturers and theirs. There's always going to be a risk. By taking on the risk and putting it on oneself, doesn't mean that it would/should be done in haste and without proper due diligence in research and meticulous, accurate execution of the layup process. The layup process isn't rocket science, and requires tools and materials that can be easily procured nowadays.

Sure. Tell that to some of the pros whose bikes buckled underneath them, and if they got their money's worth out of the professionals who built their bikes. I take your last sentence as sarcasm, but there is actually a "professional" CF repair shop (one of how many, I don't know) online, on YouTube, that shows the process of how to repair a broken frame. It really isn't difficult, and only requires an attention and adherence to detail, patience, and providing the right conditions for the composite to fully cure.

This all being beside the point, because 1. I don't have a broken frame and 2. If I did have a broken frame, I'd certainly consider doing self-repair, but that situation's neither here nor there, so contributing opinions towards that is practically useless.

OnyxTiger

All that said... I wouldn't buy the bike.

Not because he has the circular crack lines (which could possibly be a simple surface deficiency)... but the fact that he had the nerve to circle the damn thing with a red marker. Who does that?