Forums > Off-Topic Discussion > Snapped a carbon fork. Repair or replace?

Photographer

-Ira

Posts: 2187

New York, New York, US

I had a collision today. Fortunately everyone involved is physically ok.
I think the only damage to my bike is the fork. It seems to have snapped where the carbon material is attached to the metal (aluminum?) axle joint. Here are photos to help describe the damage, http://imgur.com/OYPP5Rv

My question is: Can this be repaired?

If not, what would you suggest as a replacement?

Jun 15 13 02:12 pm Link

Photographer

Paolo Diavolo

Posts: 8785

Martinez, California, US

first off, I know nothing about nice bikes, but I do like to build stuff, and I have worked with carbon fiber.

that's totally repairable to the best of my knowledge.
seems like a simple fix.

it doesn't even look like the CF is damaged other than a little chip.
the metal part slipped out because the epoxy failed.
so figure out what the best glue is, and goop it up and shove it in
(that's what she said).

Jun 15 13 02:19 pm Link

Photographer

-Ira

Posts: 2187

New York, New York, US

Paolo Diavolo wrote:
first off, I know nothing about nice bikes, but I do like to build stuff, and I have worked with carbon fiber.

that's totally repairable to the best of my knowledge.
seems like a simple fix.

it doesn't even look like the CF is damaged other than a little chip.
the metal part slipped out because the epoxy failed.
so figure out what the best glue is, and goop it up and shove it in
(that's what she said).

thanks. i suppose if you take into consideration the fact that normal riding shouldn't stress that joint laterally than finding an adequate bond between those materials should be enough.

Jun 15 13 02:29 pm Link

Photographer

Paolo Diavolo

Posts: 8785

Martinez, California, US

-Ira wrote:
thanks. i suppose if you take into consideration the fact that normal riding shouldn't stress that joint laterally than finding an adequate bond between those materials should be enough.

go get some two part epoxy that will bond metal and _____ . You should be good. Carbon fiber probably won't be one of the things listed in the blank but if it says fiberglass you'll be good.

Ask someone at a hardware store for suggestions on epoxy.
If they are all idiots, then ask someone at a Bike shop or Boat repair place what they would recommend to bond CF to metal.

Jun 15 13 02:36 pm Link

Photographer

Paolo Diavolo

Posts: 8785

Martinez, California, US

I did a little research and it seems like JB Weld should do the trick.
Just make sure you clean both surfaces, mix it correctly, and give it a full day to cure.

http://www.jbweld.com/wp-content/uploads/2012/08/productFull2.jpg

I've used the stuff before on a car part that is under stress and heat, and its held up fine for over 2 years.

Jun 15 13 02:43 pm Link

Photographer

-Ira

Posts: 2187

New York, New York, US

Paolo Diavolo wrote:
I did a little research and it seems like JB Weld should do the trick.
Just make sure you clean both surfaces, mix it correctly, and give it a full day to cure.

http://www.jbweld.com/wp-content/uploads/2012/08/productFull2.jpg

I've used the stuff before on a car part that is under stress and heat, and its held up fine for over 2 years.

right on.  any thank you.  i will give that a shot.

Jun 15 13 03:42 pm Link

Photographer

-Ira

Posts: 2187

New York, New York, US

for the record.  MM outperformed Reddit with a viable solution (assuming I don't die)

Jun 15 13 03:43 pm Link

Photographer

Cherrystone

Posts: 36697

Columbus, Ohio, US

This is what I'd be doing.
http://www.carbonframerepair.com/

Jun 15 13 04:19 pm Link

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Michael Bots

Posts: 5959

Kingston, Ontario, Canada

3 decades ago I glued the steel hinge back onto a toolbox with a high grade epoxy labeled as "3M Structural Adhesive Kit".   Still holding strong.

Sourced through auto body repair wholesalers at the time but Amazon lists it now.
http://www.amazon.com/3M-08101-Structur … B000KZUTCY


http://solutions.3m.com/wps/portal/3M/e … 3HXBTMF8gl    (aircraft version)

http://solutions.3m.com/wps/portal/3M/e … 3DG0G292bl

Try it out on something other than the bike first to see how it behaves - it's fast setting.
Spend a minute working the adhesive into the delaminated areas at the tube ends.

Jun 15 13 04:57 pm Link

Photographer

Instinct Images

Posts: 22641

San Diego, California, US

-Ira wrote:
for the record.  MM outperformed Reddit with a viable solution (assuming I don't die)

I think you have to weigh the following: cost of repair, cost of replacement, potential consequences of repair failing.

Do you ride fast? How badly could you be hurt if the repair failed? Is it worth the risk?

My recommendation is to replace the fork.

Jun 15 13 06:54 pm Link

Photographer

ImagineAerie

Posts: 402

Plano, Texas, US

Just bought a bike.  Came with an unlimited lifetime warranty -- frame breaks for any reason, they replace the bike.  Any chance?

Jun 15 13 11:47 pm Link

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Mortonovich

Posts: 5535

San Diego, California, US

Man, that is way too scary of an area to try a repair you are not
totally sure of.

Cherrystone wrote:
This is what I'd be doing.
http://www.carbonframerepair.com/

This seems like the best cost effective alternative.

Jun 16 13 12:42 am Link

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Photographer

Robb Mann

Posts: 10650

Baltimore, Maryland, US

Not all carbon fiber can be repaired. Many a Ferrari F40's have gone down with irreparable frame damage. Unless we have a resident expert, i'd check with your local bike shop.

Jun 16 13 03:43 am Link

Photographer

Red Sky Photography

Posts: 3324

Germantown, Maryland, US

There is a lot of vibration when you ride, and a very small area to glue back together. I'd feel much safer having it repaired professionally or replacing the fork.

Perhaps as another has suggested, check for a warranty on the fork.

Jun 16 13 09:44 am Link

Photographer

Cherrystone

Posts: 36697

Columbus, Ohio, US

Cherrystone wrote:
This is what I'd be doing.
http://www.carbonframerepair.com/

ChiMo wrote:
Man, that is way too scary of an area to try a repair you are not
totally sure of.

This seems like the best cost effective alternative.

I had this vision of flying downhill at about 40-50mph, hit a bump of some sort, the DIY carbon repair fails, and I'm suddenly flying like Superman. wink

Jun 16 13 09:48 am Link

Photographer

Wye

Posts: 9887

Toronto, Ontario, Canada

I would replace it.

I like having all my bones intact more than I like having a little bit of extra money in my wallet.

Jun 16 13 09:52 am Link

Photographer

Dark Shadows

Posts: 2269

Miami, Florida, US

I'm an avid cyclist, and my suggestion to you is to replace the fork as it's not really that expensive a repair.

This one here is $90 brand new, and it's all carbon, not carbon bonded to metal: http://www.nashbar.com/bikes/Product_10 … 4979_-1___

Jun 16 13 12:15 pm Link

Photographer

Paolo Diavolo

Posts: 8785

Martinez, California, US

Robb Mann wrote:
Not all carbon fiber can be repaired. Many a Ferrari F40's have gone down with irreparable frame damage. Unless we have a resident expert, i'd check with your local bike shop.

^ makes no sense.
a Ferrari f40's frame is NOT carbon fiber.

its not hard to repair fiberglass or carbon fiber.
in the case of this thread:
it appears only the bond (glue) between the metal and the CF fork failed. the CF doesn't look cracked or damaged.

Jun 16 13 01:42 pm Link

Photographer

Vintagevista

Posts: 11037

Sun City, California, US

If it's not all that expensive to replace - I'd replace something like that for peace of mind.

Yes, you might repair it - but, I'd have trouble trusting repairs of such a critical piece.

I would think in terms of trust in replacement - versus the consequences of a failure of the repair - at the worst possible moment.

Jun 16 13 03:30 pm Link

Photographer

The F-Stop

Posts: 1510

New York, New York, US

Replace it!

I'd hate to have it go on a ride.. head over bars?.. NO FREAKIN WAY! Collar bone, broken hip, fly off into traffic.. I hope you at least wear a brain bucket?

Jun 16 13 04:04 pm Link

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MMR Digital

Posts: 1716

Doylestown, Pennsylvania, US

Replace the fork or otherwise we'll need to send flowers. Not!

Jun 16 13 04:56 pm Link

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Art Silva

Posts: 9451

Santa Barbara, California, US

Military grade Duct Tape!  tongue

Jun 16 13 09:52 pm Link

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GPS Studio Services

Posts: 36241

San Francisco, California, US

So we are talking about risking your life to save the price of a $90 part?  I agree it is completely repairable.  It will be fine, unless it isn't.  On your way to the hospital you will be kicking yourself for not having done it right.

Jun 16 13 10:00 pm Link

Photographer

-Ira

Posts: 2187

New York, New York, US

Sold.  Decided I'd probably be nervous zooming downhill on my own repair.  Ordered a new fork.  Thanks Dark Shadows for the heads up on Nashbar.

Jun 19 13 10:58 am Link

Photographer

Instinct Images

Posts: 22641

San Diego, California, US

You'll never regret not crashing.

Jun 19 13 12:49 pm Link

Photographer

Right Poes

Posts: 908

Colorado Springs, Colorado, US

ImagineAerie wrote:
Just bought a bike.  Came with an unlimited lifetime warranty -- frame breaks for any reason, they replace the bike.  Any chance?

agreed should be covered.

Jun 19 13 01:04 pm Link