Any Carbon Fibre Experts?

[V8 Stang]

So i have a Carbon Framed E- Mountain Bike, and have been getting some creaking/cracking sounds coming from the headset on big hits.
And can replicate it by bouncing the front end hard.

Having replaced both upper and lower headset bearings and cup's its still the same.

However i have noticed the Carbon on the frame where the lower cup and bearing gets pressed into does not look right.



So one side you can see the CF Weave, then on the other its like its been ground down and some filler in there.

Is this right for a precision finish? A 56mm cup gets pressed into it. Has something gone wrong in the manufacturing of the frame and been repaired? Would this repair cause a weakness - hence the creaking/cracking sound?

The top mount is perfectly uniform with carbon weave all around?


What do we think?

Cheers

[zb]

Think it's delaminating.

[jamiem555]

Not an expert on bikes but do work on helicopters with lots of composites. As the second post says, quite clearly delaminating. Whether it’s repairable or not I couldn’t say. More than likely the cause of the noise.

[nickfrog]

I can't help either except asking if you fitted carbon paste between the frame and the cups? I know you're asking about the structural integrity and rightly so but should that be cleared then perhaps the paste would lncrease friction and stop the creaking?

[Rough101]

That’s delaminating as mentioned, but with the cup pressed in, that makes the strength up, try with carbon assembly paste.

‘Holes’ in carbon bike frames are never round, and often reamed round after curing, some of it is hyperbole, and a lot of it sexist, but Hambini on YouTube correctly identifies this, other than with French frames, most mainstream bike carbon is really poor on tolerances.

[V8 Stang]

zb said:

Think it's delaminating.

Thanks, what is likely to have caused this? manufacturing issue? The bike is only 10 months old.

nickfrog said:

I can't help either except asking if you fitted carbon paste between the frame and the cups? I know you're asking about the structural integrity and rightly so but should that be cleared then perhaps the paste would lncrease friction and stop the creaking?

The new cups came with carbon paste which i used on re-assembly, but still have noises coming from the headset area.

However interestingly, the cups only go half way up the area, you can kind off see the line. the top still seems de-laminating, but not as bad as the bottom half where the cup sits?

Rough101 said:

That’s delaminating as mentioned, but with the cup pressed in, that makes the strength up, try with carbon assembly paste.

‘Holes’ in carbon bike frames are never round, and often reamed round after curing, some of it is hyperbole, and a lot of it sexist, but Hambini on YouTube correctly identifies this, other than with French frames, most mainstream bike carbon is really poor on tolerances.

Yes i understand im not getting the best quality carbon fibre on an entry level carbon bike, but it shouldn't start delaminating after 10 months and 1500 miles use.

Its a "21 Cube Stereo 160 for reference, paid £5K. So whilst its a more budget E-MTB, its still a fair chunk of cash.


Its booked into a Cube store to have a look next week, but feel they may not really have the experience of Carbon to get to the bottom of it?

[normalbloke]

If it is delaminating, then surely the frame is done?

[V8 Stang]

normalbloke said:

If it is delaminating, then surely the frame is done?

I think a specialist could probably repair it, but pretty certain Cube won't. But also getting cube to replace the frame under warranty i feel will also be a fight....


The other thing that has happened is the compression ring on the top bearing has scored around the steerer tube on my Zeb!






My sort of theory is that the carbon head has been flexing (hence the noise) which has then been causing the compression ring to dig into the steerer tube?

Im very certain ive not had a loose headset, which i suspect is what cube will try blaming. But even if it was a loose headset, i don't see this would have caused damage to the headtube, as the cup is tightly pressed in?

[oddball1313]

There’s a few Uk companies doing carbon bike repairs,

had a chain stay repaired by these guys - was good as new when i got it back

https://www.carboncyclerepairs.co.uk/

These guys have a good name as well

https://carbonbikerepair.co.uk/wp/

[W12GT]

I’m looking at getting myself a new gravel bike, at the beginning I considered carbon frame and forks, but having spoken to a couple of friends who are heavily into their cycling (road and MTB) they have both had quite serious accidents where forks or frames have failed.

Seeing things like this reinforces my decision to go alloy.

Good luck with getting it sorted quickly and safe riding!

[nickfrog]

That's perhaps where titanium may offer the best of both worlds on a gravel bike, but at a cost.

[dontlookdown]

That doesn't look too clever. I wouldn't take it any deeper than about 10 feet if I were you;)

[Gummi]

I think the frame and fork are toast unfortunately. The cause is likely a loose headset.

[nickfrog]

Gummi said:

I think the frame and fork are toast unfortunately. The cause is likely a loose headset.

How would that happen? Frame too big and cup movements under load against the walls?

[V8 Stang]

nickfrog said:

Gummi said:

I think the frame and fork are toast unfortunately. The cause is likely a loose headset.

How would that happen? Frame too big and cup movements under load against the walls?

Thats what i don't understand, the cup is pressed into the frame pretty solidly, it needed some good whacks to remove it.
And it can't have been spinning sideways, as it has the acros lockstop (limits steering angle), and would notice the bars out of whack.

For that cup to be moving would require the headset to be soo loose, it would be obvious and completely dangerous to ride.

And the fact the head tube is worn/de-laminated above where the cup even sits.

[bobbo89]

And this is why I don't like carbon fibre anything when it comes to bikes. Sorry OP as this isn't a helpful post in the slightest but I genuinely think CF is the worst material to use if you want a bike that'll last. BB's and headsets are destined to fail on CF frames and other components like handlebars can't take clamping forces.

I've been stung by CF parts failing and I've no interest in it anymore. Steel or aluminium is where it's at. I'm even a bit dubious about titanium as it seems prone to cracking.

[V8 Stang]

So i took the bike back to the supplying dealer on Tuesday (6 hour round trip!), he had a look at the photo's and thinks it looks like the cup has been slipping causing wear - but not seen it before on these bikes.

Said he will strip it down, take photo's and submit a warranty claim with cube, and push for new frame and fork. But was pretty vague on whether the claim is likely to be approved and potential repair timeframe.

Apparently it takes 7-14 days just to hear back from cube regarding the warranty case!


So what is a reasonable time frame for things to be sorted before starting to push the store? As its very disappointing to not have a bike during peak season!

[nickfrog]

bobbo89 said:

BB's and headsets are destined to fail on CF frames and other components like handlebars can't take clamping forces.

I never had issues with BB or HS areas but perhaps I was lucky.

As for CF bars I have only been using them for 15 years and just complied with the torque values supplied, again with zero issues.

[bobbo89]

nickfrog said:

I never had issues with BB or HS areas but perhaps I was lucky.

As for CF bars I have only been using them for 15 years and just complied with the torque values supplied, again with zero issues.

I'm probably just bitter having had to put up with a very expensive and creaky Intense carbon frame. I've also had mates and colleagues have issues, particularly with BB's creaking their tits off. I just think it's a compromised material when used in a certain way and that carbon headtubes and BB shells are ste.

Where it looks to be good though is where companies like Atherton and now Pivot are using it by bonding CF tubes into CNC'd ti joints. Depending on how good the bond is that application of both CF and Ti looks to optimise the characteristics of both.

[V8 Stang]

So Cube want my bike returned to Germany so they can fully inspect it and find the cause. Been told it will be 2-3 weeks to get there and be inspected!


So have been having a look at some normal Enduro bikes, as kind of fancy a proper enduro bike for uplift bike park days.

And came across the Nukeproof Giga 297, half price on chain reaction for £1849! ordered it yesterday, hopefully get it by the weekend!
Its only the base model, but spec still looks decent, and 180mm front and rear travel!

https://www.chainreactioncycles.com/p/nukeproof-gi...


Darn biking is expensive!

And yes ive just ordered another Carbon bike after having a different carbon bike fail