Repair Cracked Carbon Frame

[spdrrr]

Hi,

Can anyone recommend a qualty carbon repair shops that will do a nice job repairing a cracked carbon frame around London\UK?

Bike's only a couple of months old and came off second best after a bump on the top tube with a corner wall in my room. It's a small crack only maybe 5mm long, but there's a definate hole there and some plaster wedged in.

I've googled a bit and found a few places, but really looking for some positive recomendations from anyone out there that's had their pride and joy repaired.

ta
Stu

 

[RidingSeed]

I would really not repair a carbon fiber frame. I'd really just change it. Carbon fiber is not the same after it's been damaged, so you're most likely to have problems more often.

 

[laziali]

I would really not repair a carbon fiber frame. I'd really just change it. Carbon fiber is not the same after it's been damaged, so you're most likely to have problems more often.

Don't listen to this. Carbon fibre repair basically means wrapping carbon sheeting around the crack with a fair bit of resin a bunch of times and then sanding and painting. The more wraps and resin, the stronger. Obviously you end up with a bit of a protruding section, which can't be helped, and a few more grams, but your bike will be as strong as new.

 

[Master50]

In truth a good carbon repair will fully restore a frame to safe ridability. Often the repaired area will be stronger like a broken bone gets stronger right at the break. It can change the feel of the frame by adding material in places that might not need it but in no way would the bike be less safe or functional. Some carbon frames are tube and lug construction and entire tubes can be cut out and replaced. These full tube replacements can fully restore a frame to original spec.
Carbon is often easier to repair than steel.

 

[RidingSeed]

In truth a good carbon repair will fully restore a frame to safe ridability.

A good job done, yes, should bring the bike back to normal, but a poor job done can bring accidents not long after repairing.

Don't listen to this. Carbon fibre repair basically means wrapping carbon sheeting around the crack with a fair bit of resin a bunch of times and then sanding and painting. The more wraps and resin, the stronger. Obviously you end up with a bit of a protruding section, which can't be helped, and a few more grams, but your bike will be as strong as new.

From what I know, the protruding section will cause weakening in the area around where the crack used to be, and over time, depending on what kind of terrain you're riding on, more cracks will appear.

 

[laziali]

From what I know, the protruding section will cause weakening in the area around where the crack used to be, and over time, depending on what kind of terrain you're riding on, more cracks will appear.

This one is news to me, although my experiences with carbon repair are on road bikes not MTB. Do you have any links or more info for this issue?

 

[Master50]

A good job done, yes, should bring the bike back to normal, but a poor job done can bring accidents not long after repairing.

Always true of any repair! Go to a repairer that is good.

From what I know, the protruding section will cause weakening in the area around where the crack used to be, and over time, depending on what kind of terrain you're riding on, more cracks will appear.

I have heard that of bones but again lets go to the first premise. Start with an experienced carbon repair person with a reputation and that might be the challenge. In North America Calfee is a great shop.

 

[RidingSeed]

This one is news to me, although my experiences with carbon repair are on road bikes not MTB. Do you have any links or more info for this issue?

When the carbon fiber gets cracked, fibers separate, and therefore a repair will not be able to reconnect them. Compaction will not be the same and eventually all the fibers will follow the same path, resulting in a potential injury. Here's a link you can take a look at. Click here.

 

[laziali]

When the carbon fiber gets cracked, fibers separate, and therefore a repair will not be able to reconnect them. Compaction will not be the same and eventually all the fibers will follow the same path, resulting in a potential injury. Here's a link you can take a look at. Click here.

Thanks - interesting read.

 

[Master50]

When the carbon fiber gets cracked, fibers separate, and therefore a repair will not be able to reconnect them. Compaction will not be the same and eventually all the fibers will follow the same path, resulting in a potential injury. Here's a link you can take a look at. Click here.

Another quote from the same article below

"Let’s say you run out of talent in a big way, and crush some fiber along with your own bones. The good news is carbon can be repaired. You might not believe this, but often it is easier and less expensive to repair than Aluminum, Ti or Steel. An impact that severely dents an aluminum tube might need a tube replaced. Aluminum bikes are heat treated, so in addition removing and replacing the old tube (if it can be removed), you need to also heat treat, realign and repaint or reanodize the frame. None of this is necessary with a carbon frame."

So I suppose if you use an article to make your point you should also check to see if it refutes it too.

Like everyones says it also matters who you use to fix it but CF is very repairable and once properly repaired will last and be safe.

 

[RidingSeed]

Another quote from the same article below

"Let’s say you run out of talent in a big way, and crush some fiber along with your own bones. The good news is carbon can be repaired. You might not believe this, but often it is easier and less expensive to repair than Aluminum, Ti or Steel. An impact that severely dents an aluminum tube might need a tube replaced. Aluminum bikes are heat treated, so in addition removing and replacing the old tube (if it can be removed), you need to also heat treat, realign and repaint or reanodize the frame. None of this is necessary with a carbon frame."

So I suppose if you use an article to make your point you should also check to see if it refutes it too.

Like everyones says it also matters who you use to fix it but CF is very repairable and once properly repaired will last and be safe.

It CAN be repaired, but it will not be as strong as it was before and it is more likely to cause problems earlier than it would normally do. Carbon fiber is meant to resist being bent, but it has very low resistance to cracking and hitting.

 

[oncehadhair]

When the carbon fiber gets cracked, fibers separate, and therefore a repair will not be able to reconnect them. Compaction will not be the same and eventually all the fibers will follow the same path, resulting in a potential injury. Here's a link you can take a look at. Click here.

from your article:
"The good news is carbon can be repaired. You might not believe this, but often it is easier and less expensive to repair than Aluminum, Ti or Steel"

I've had seat stays on a carbon fibre bike repaired after a crash and the cracked bottom bracket on an aluminium bike repaired with carbon fibre. Both by someone who hand builds carbon bikes. Both great jobs with no noticeable loss of rigidity no evidence of failure after thousands of kilometres.

You have shot yourself in the foot.

 

[King Boonen]

It CAN be repaired, but it will not be as strong as it was before and it is more likely to cause problems earlier than it would normally do. Carbon fiber is meant to resist being bent, but it has very low resistance to cracking and hitting.

Again, from the link you provided:

"Most of the layup of our carbon frames finds the carbon prepreg in 0º, 30°and 45º orientations. The 90º weave you often see as the top layer provides the resistance to impact. So while the common worry is about flying rocks cracking your frame the truth is that of the thousands of Mojos we’ve made over the years, the number that have actually broken this way can be counted on one hand. "

 

[Master50]

It CAN be repaired, but it will not be as strong as it was before and it is more likely to cause problems earlier than it would normally do. Carbon fiber is meant to resist being bent, but it has very low resistance to cracking and hitting.

Again, An expert who knows all the materials strengths and weaknesses can compensate for all these factors and restore the frame to full utility at least equal to original and often even stronger than original as it is not too hard to over compensate. The simple fact that well engineered CF frames can exceed any other material for toughness, strength, and even impact. I am sure you have seen Santa Cruz bang the downtube of a cf frame against the corner of a concrete block wall? Will a CF repair change the ride? maybe but not necesarily in a bad way.
Your claims stopped being true 5 or more years ago as more and more companies get competent with CF and fixing it. If anything over fixing it is likely a bigger problem than fixing it enough. These fears of yours have been addressed. The only true thing is it is still hard to find good repair people that can reliably deal with the special intricacies of CF repairs and have enough experience to prove they do. Calfee has proven it is a very competent CF repairer and I know there are others too.

 

[Moose McKnuckles]

It CAN be repaired, but it will not be as strong as it was before and it is more likely to cause problems earlier than it would normally do. Carbon fiber is meant to resist being bent, but it has very low resistance to cracking and hitting.

No, this is just not true. Why do you keep posting false statements?

I've seen Calfee's work on my friend's bike. He rode and raced it for years after the repair.

http://calfeedesign.com/repair/repair-technique/

 

[veganrob]

No, this is just not true. Why do you keep posting false statements?

I've seen Calfee's work on my friend's bike. He rode and raced it for years after the repair.

http://calfeedesign.com/repair/repair-technique/

Yes. Calfee replace the entire chainstay on a Cervelo R3 for a friend and he is still racing it 3 years later. Hell, it is stronger than the rest of the bike now.