Dengfu E10 fibreglass in frame?

[Azar]

So after cracking two E10 frames in the same location I decided to get one fixed. After chatting to the repairer I was surprised and pissed off to find out that the frame contained fibreglass between the inner and outer layers of carbon. Has anyone else cut into or sanded their frames and discovered fibreglass?
Photos are of both frames and their cracks.

 

[Karamba!]

Wow, you broke my heart (newly owner of one myself ).
2 frames broken, nearly on the same area, is unlikely a coincidence.
Under exactly what circumstances those cracks happened?
Did your tech spot glass fiber on both frames?
I hope that @Ben Rides from Dengfu shows up and provide an explanation

 

[TQFreak]

Mixing fiberglass and carbon fiber you get less fragile and more crack resistant material than using carbon fiber alone. It is also OK to put fiberglass in the middle layer between the carbon fiber layers because of the middle layer experiences less stress than external layers.

It looks like you ran in to the wall with the front wheel or something to collapse the frame like that. How it happened?

 

[VardyR]

How did the damage occur ?
They both look like impact damage rather than one done under tension as you would expect at that point of the frame unless you did a 180 and landed on the handlebars

 

[Azar]

So, both frames have cracked under tension from riding and not from accidents or impacts.
Frame one cracked after landing a medium sized jump but after seeing what happened to the second frame I suspect it may have started cracking earlier and I didn’t see it as it was under a frame skin.
Frame 2 has progressively cracked over the last couple months, the bike is still built and ridden but not jumped.
The repair has been made to the first frame only so I don’t know if the second frame has fibreglass in its layup?

 

[Karamba!]

So, both frames have cracked under tension from riding and not from accidents or impacts.
Frame one cracked after landing a medium sized jump but after seeing what happened to the second frame I suspect it may have started cracking earlier and I didn’t see it as it was under a frame skin.
Frame 2 has progressively cracked over the last couple months, the bike is still built and ridden but not jumped.
The repair has been made to the first frame only so I don’t know if the second frame has fibreglass in its layup?

That´s very worrisome. This is the first time I see reports of cracks or failures due to riding, let alone 2 frames. I wonder if there are more cases like yours.
BTW: Do you consider yourself as a hardcore/extreme rider? Without the intention of being nosy, how much do you weight?

 

[Azar]

That´s very worrisome. This is the first time I see reports of cracks or failures due to riding, let alone 2 frames. I wonder if there are more cases like yours.
BTW: Do you consider yourself as a hardcore/extreme rider? Without the intention of being nosy, how much do you weight?

I wouldn’t say hardcore or extreme anymore. I’m 100kg and the other side of 50. I work as a MTB instructor part time and I can ride pretty well. I’m not crashing into walls if you know what I mean.

I do believe there is either a layup or design flaw in the key hole area of the E10 frame (at least with the two frames I have).

I absolutely love the bike and other than the cracking in the key hole area the bike has been rock solid and rides really well.

 

[Hardtail]

Search fibreglass in carbon bike frames on Youtube.

 

[Karamba!]

Search fibreglass in carbon bike frames on Youtube.

Interesting. That raises the question why Dengfu used it in this case. Is it because the battery holder could introduce corrosion when touching the carbon, or is it merely to cut cost?
Ben from Dengfu should chime in to give light to the issue. This is quite unsettling for new owners.

 

[Karamba!]

I wouldn’t say hardcore or extreme anymore. I’m 100kg and the other side of 50. I work as a MTB instructor part time and I can ride pretty well. I’m not crashing into walls if you know what I mean.

I do believe there is either a layup or design flaw in the key hole area of the E10 frame (at least with the two frames I have).

I absolutely love the bike and other than the cracking in the key hole area the bike has been rock solid and rides really well.

Did your tech guy told you how reliable the frame will be after the fix? How much the repair costed? What did they do exactly?

 

[Hardtail]

@Azar Are you near Brisbane? you should take the frame into Gary at Carbon Steed.
https://carbonsteed.com.au

 

[Waynemarlow]

There is a substrate of glass fibres in a specialist cloth that is used not as a filler as being described, but as a spacer to give width between the outer and inner carbon layers, which makes the structure significantly stronger and lighter than solid carbon.

Most aircraft composite construction is of carbon - foam- carbon but in very small mouldings with complicated surfaces, then they use this specialist glass cloth to separate the carbon skins in the pressure moulding needed for the modern infusion techniques being used.

The downside of it is that direct pressure to the outer skin can flex the carbon which carbon tends to dislike a lot. Can we ask whether this damage is being caused not by riding the bike but something like a bike carrier or say the frame being hung over the back of a pickup tailgate perhaps. That frame damage is not being reported by other owners so perhaps it could be something unique to that owners useage.

My guess would be that Dengfu would already have altered the layup schedule in that area if they have seen the photos, its a pretty simple fix at the layup and moulding stage.