Alu/Carbon frame issue

emy

Hi all,
I went today for a spin, I was doing around 45KM/h, I notice a weird sound coming from the rear wheel. When I looked at it, the wheel was rubbing the bottom fork of the headtube. I stopped it and just putting my weight (80kg) on the saddle the wheel, which was tight, (all the nuts in good working order), was going sideway. When I got home I checked the entire rear side. I noticed that the left side of the bottom fork is coming out, it is like a tube that goes into the fitting that holds the wheel. The frame is made by aluminum with both forks by carbon. There is any way to fix it, some kind of strong glue, to keep it in, stopping coming out?
Thanks

Phil.x

Can't see a home diy doing a proper job. Maybe check to see if theres a long frame guarantee.

emy

Phil.x wrote: »

Can't see a home diy doing a proper job. Maybe check to see if theres a long frame guarantee.

Thank for quick reply. If I go to a bike service center, is it anything that can be done do get it fixed? There is no warranty on this bike anymore.

magicbastarder

as above, i'd bring that to a pro. to reglue it properly might be beyond a garden shed job.

emy

Thanks both for help. I have spoken a "pro" guy who is dealing with carbon frame repairing, unfortunately he has no Alu/Carbon bond, only carbon to carbon. I might fix it by myself, thinking of getting the strongest Epoxy resin available (3M™ Scotch-Weld™ Epoxy Adhesive), but first I will be drilling a hole through both, aluminum and carbon, and use a strong steel pin, together with Epoxy it will get me a few more hundreds on KMs.

Vestiapx

emy wrote: »

Thanks both for help. I have spoken a "pro" guy who is dealing with carbon frame repairing, unfortunately he has no Alu/Carbon bond, only carbon to carbon. I might fix it by myself, thinking of getting the strongest Epoxy resin available (3M™ Scotch-Weld™ Epoxy Adhesive), but first I will be drilling a hole through both, aluminum and carbon, and use a strong steel pin, together with Epoxy it will get me a few more hundreds on KMs.

i wouldn't drill it just glue it, rough up the alu as much as you can and get it as clean as possible first, if a lock pin would have helped it would have come with one.

emy

Vestiapx wrote: »

i wouldn't drill it just glue it, rough up the alu as much as you can and get it as clean as possible first, if a lock pin would have helped it would have come with one.

If it is true what that Epoxy does, there is no need of any pin.

magicbastarder

Vestiapx wrote: »

i wouldn't drill it just glue it, rough up the alu as much as you can and get it as clean as possible first, if a lock pin would have helped it would have come with one.

would that not be part of the problem - the bike would originally have been glued up with the whole of the aluminium part accessible, so unless emy can take it out completely, won't be able to get the same sort of coverage on the part?

ednwireland

surely if you drill it you will just create crack initiation sites ?

mad turnip

I had an MTB frame fail in exactly the same way. The bond between the carbon and aluminum on the rear triangle of a full suspension separated. Considering it was for MTB and would take some proper hits I just wrote the frame off. Being a roadbike there may be more help available.

A few people I talked to did suggest epoxy but for an MTB frame not a chance.
Like you I felt something weird and luckily I did because I was about to hit a fairly big bomb hole which would have probably broken the frame in half and me with it.

In regards to fixing it I wouldn't put a drill anywhere near carbon. I'd try pulling out that joint as much as possible getting epoxy on everything and shoving it back in . As someone said above roughing it up would help but not sure how easily that will be depending on how stiff those chain stays are. I know on my mtb I could pull the whole thing out easily enough to do a fix like this.

Mefistofelino

A proper "home" repair should be possible but it will be all about the preparation. Browse the various composite fabrication sites to see what is recommended for aluminium / carbon bonding - it may not a generic multipurpose epoxy.
The joint needs to be cleaned properly - both inside the carbon chainstay and the alloy lug. You will need to pull the lug back to expose the plug along its length and not try to inject the epoxy along the small gap as per your photo. As others have noted, don't drill / pin it
The epoxy should be prepared and applied as per the manufacturing instructions. Also pay attention to curing time and temperatures - if the instructions say leave for 72 hours at > 20°C (or whatever) to achieve full strength then do at least that. Don't apply it in a cold, damp shed at 5°C and start hauling at it the following morning.

Alternatively, if you can source the correct adhesive, would the carbon guy take the job on for you then? He'll have considerably more experience.

What would concern me more is that the joint which failed is just one of several on the frame that were bonded using the same adhesive at the same time and have had the same exposure to the elements etc.

emy

magicbastarder wrote: »

would that not be part of the problem - the bike would originally have been glued up with the whole of the aluminium part accessible, so unless emy can take it out completely, won't be able to get the same sort of coverage on the part?

I have a max 1cm gap available, I can not pull out more, I am afraid do not damage the other side. Drilling the carbon is out of question, if was only aluminum it could have been done without any risks, I think, carbon never drilled before.

Vestiapx

emy wrote: »

I have a max 1cm gap available, I can not pull out more, I am afraid do not damage the other side. Drilling the carbon is out of question, if was only aluminum it could have been done without any risks, I think, carbon never drilled before.

1 cm should be enough, if you warm the epoxy and agitate the joint and add a bit more i think it would have a good chance of sticking, thats all the pros will do and they wont stand over it anyways.

emy

I have noticed that there is a screw holding the aluminum side in two pieces together, it was covered in black paint, therefore I could not see it. I removed it, cleaned it, now waiting for the glue. Also there is a small crack at the end of carbon fork, I ll try to get a carbon fix kit to give it a try, if does not work I might look for a new frame.