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Forums > Off-Topic Discussion > Snapped a carbon fork. Repair or replace? Search   Reply
Photographer
-Ira
Posts: 2,180
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  Quote 
Photographer
Paolo Diavolo
Posts: 8,269
Pleasant Hill, 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  Quote 
Photographer
-Ira
Posts: 2,180
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  Quote 
Photographer
Paolo Diavolo
Posts: 8,269
Pleasant Hill, 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  Quote 
Photographer
Paolo Diavolo
Posts: 8,269
Pleasant Hill, 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  Quote 
Photographer
-Ira
Posts: 2,180
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  Quote 
Photographer
-Ira
Posts: 2,180
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  Quote 
Photographer
Cherrystone
Posts: 36,219
Columbus, Ohio, US


This is what I'd be doing.
http://www.carbonframerepair.com/
Jun 15 13 04:19 pm  Link  Quote 
Photographer
Michael Bots
Posts: 5,598
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  Quote 
Photographer
Instinct Images
Posts: 22,494
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  Quote 
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  Quote 
Photographer
Mortonovich
Posts: 5,305
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  Quote 
guide forum
Photographer
Robb Mann
Posts: 10,121
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  Quote 
Photographer
Red Sky Photography
Posts: 3,270
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  Quote 
Photographer
Cherrystone
Posts: 36,219
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  Quote 
Photographer
Wye
Posts: 9,529
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  Quote 
Photographer
Dark Shadows
Posts: 2,269
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  Quote 
Photographer
Paolo Diavolo
Posts: 8,269
Pleasant Hill, 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  Quote 
Photographer
Vintagevista
Posts: 10,702
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  Quote 
Photographer
The F-Stop
Posts: 1,437
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  Quote 
Photographer
MMR Digital
Posts: 1,670
Doylestown, Pennsylvania, US


Replace the fork or otherwise we'll need to send flowers. Not!
Jun 16 13 04:56 pm  Link  Quote 
Photographer
Art Silva
Posts: 9,053
Santa Barbara, California, US


Military grade Duct Tape!  tongue
Jun 16 13 09:52 pm  Link  Quote 
guide forum
Photographer
GPS Studio Services
Posts: 35,022
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  Quote 
Photographer
-Ira
Posts: 2,180
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  Quote 
Photographer
Instinct Images
Posts: 22,494
San Diego, California, US


You'll never regret not crashing.
Jun 19 13 12:49 pm  Link  Quote 
Photographer
Right Poes
Posts: 848
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  Quote 
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