Carbon rim wrinkling and bubbling

[hugh]

The carbon front wheel on my 5 month old Giant TCR has wrinkled and bubbled out along about 40cm of the rim. 00921C34-D49F-4B53-B2BC-8895796C5DB1.jpg


Hasn’t been on a hitch rack next to an exhaust or exposed to any high temps.

It’s back in the shop waiting on a warranty assessment. Fingers crossed it all gets sorted out.

There are a few examples on the internet of very similar failures to the same wheel where apparently a warranty had been denied as Giant claimed heat damage from being left in the back of a hot car.

Is it even plausible that the 70c/160f temps that a really hot car might reach could cause a wheel to fail like this?

[vertical_doug]

If you think the resin in the carbon fiber becomes unstable at 70c, the wheel is inherently unsafe to ride in the mountains. You'd expect in hard breaking the inability of the wheel to dissipate heat could cause catastrophic failure with hard rim braking.

It looks like your wheel has no brake track, so I assume a disc brake. I suspect they are trying a cheaper design and resin because they need less heat dissipation. I'd complain about the resin and unsafe design.

[j44ke]

Looks like it is only in that section next to the valve? Is that the rotational direction of the wheel - the valve then the wrinkles? And is it on the disc side of the wheel? Almost looks like the wrinkles are created by directional forces if so - riding is creating wrinkles. Some kind of delaminating. But in one area. If all the wheels that exhibit this problem are showing it in the same area, that would be interesting too.

[htwoopup]

I can’t speak specifically to wheels as I have always left that to smarter carbon people on this forum.

But if I saw this on a boat hull (where I do have a boat load of experience), I would say that is shitty layup of the carbon. Simplistically, the carbon mat wasn’t put in the mold correctly. I am saying that because it almost looks like it is a seam/ where two carbon mats overlaid each other. Which, if that is in fact what it is, is absolutely beyond me why one would use mat like that rather than a single piece cut in a circle. It also looks like the mat wasn’t laid into the mold evenly and squeeged/pressed out properly. Again, perhaps I am way off base because they might layup wheels differently than they lay up boat hulls. But that ain’t right and I am not buying that it is a resin problem or a « user error heat problem » because if it is I think the real reason is the underlying shitty production. I have also seen bad batches of resin but the seam-like appearance makes me think something else is going on. Oh, and in my experience, if you are having a heat problem it isn’t the heat it was shitty resin to begin with.

[hugh]

Looks like it is only in that section next to the valve? Is that the rotational direction of the wheel - the valve then the wrinkles? And is it on the disc side of the wheel? Almost looks like the wrinkles are created by directional forces if so - riding is creating wrinkles. Some kind of delaminating. But in one area. If all the wheels that exhibit this problem are showing it in the same area, that would be interesting too.

Interesting, I hadn’t thought about that. Yes, the delamination is on the disk side and the biggest wrinkle lines up with a leading spoke which would experience increased tension under braking.

The other examples I found look much worse and less localised though
https://www.bicycles.net.au/forums/v...02825&start=50
and

[rwsaunders]

This video (Giant manufacturing process) was posted on PL today and there are scenes of folks laying up rims...

[htwoopup]

Having now watched what Bob posted, it is reminiscent of an old style cheap way of making boats with « chop blown »...essentially smaller pieces that become very resin dependent for strength...rather than the mat/fibers properly laid directionally for strength given the forces that will bear in use.

Also, I do remember I had a set of disc wheels which I had no problem with that the manufacturer called me a week after they were delivered and said do not ride them, bring them back we are replacing them for free. The reason they gave was that the resin supplier had not given them the resin they spec’d and they had noticed on one wheel of their personal wheels that the valve hole had elongated.

So, I am now convinced it isn’t your doing it is bad resin that was supplied/ or improperly spec’d for the use and what looks like a pretty crappy (I could go into other stuff in that video about the molds, handwork, mat pieces how they join, etc) production process which is a classic of save a penny here save a penny there and eventually we save real money. I would insist they warranty the wheels and I would insist that they do it out of stock that was not built on the same run/ same batch of materials. Again, I am applying what I learned in doing boats to cycling products which is a whole other engineering smoke so perhaps I am wrongly trashing Giant. But even looking at your wheel it seems very resin heavy which could explain why it seems that they are doing an awful lot of hand rework (albeit with power tools in some cases so that amplifies my concern) on a product that, if it were a 50 foot 18 ton boat would be so fine when it came out of the mold that it would require zero rework. Every time.The only rework there is when two huge pieces (like a deck and a hull) that were separately molded are joined together. Not to digress too much, but I had a boat that was 31,407 pounds for hull and deck added together when they came out of the mold that was designed to be only 6 pounds different than that. A lot has to do with the production process and some is a little out of your hands like ambient temperature during « cure » but it all can be dealt with. I would think a small bike would not need the amount of sanding that is in that video if made properly.

To blame the issue on leaving it in a car is just so no one has to admit they didn’t do it right or spec’d materials wrong or supplied them incorrectly ATMO,

[htwoopup]

Also, when we were doing some center consoles out of kevlar (the mat roving materials aren’t as important in this discussion as the production), we would have some weirdness at stress points if we didn’t get the resin really well squeezed out. Of course, that was before we went to the bladder process. But that was in the early 80’s so I would think that Giant would have this down 40 years later when working with carbon.

[j44ke]

If it is from exposing it to temps occurring in cars, you'd think there'd be more brands affected. Leaving a bike in a car is not that rare an act of oversight.

[Chik]

I'm sorry about your ordeal.

My limited exposure to CFRP manufacturing is in other applications, but I would not want a replacement. I would want a refund. I wouldn't feel comfortable rolling on another wheel that came out of the same factory / same company operating under the same procedures and standards EVEN IF (or perhaps, especially if) the cause lies outside, for example, as Jon mentioned, an out of spec resin or a cock up by the prepreg supplier.

Refund is probably out of the question if the wheel came as part of a complete bike, but no thanks to a replacement. That's just my opinion.

[Marvinlungwitz]

Bummer.

Those of us with no hope for speed can make do with alloy rims and less headaches. :-)

[claritycycler]

Bummer.

Those of us with no hope for speed can make do with alloy rims and less headaches. :-)

I'm with ya here...

[RichTheRoadie]

This video (Giant manufacturing process) was posted on PL today and there are scenes of folks laying up rims...

I am a total layman and I can't watch that and criticise methods - BUT, there is absolutely *nothing* about that video that gives me any confidence in a carbon bike out of a Giant factory, or any other factory that uses similar methods. Even I can see from that how easy it would be for voids to be created, as Luescher Teknik often finds when he cuts bikes up. Yowsers.

[rwsaunders]

I am a total layman and I can't watch that and criticise methods - BUT, there is absolutely *nothing* about that video that gives me any confidence in a carbon bike out of a Giant factory, or any other factory that uses similar methods. Even I can see from that how easy it would be for voids to be created, as Luescher Teknik often finds when he cuts bikes up. Yowsers.

It is amazing, isn't it? I told my one friend after I watched the video, that I'm sticking with my old, weathered and sluggish Nucleon and Nemesis wheels.

[rwsaunders]

Here you go Rich...another winner.

[RichTheRoadie]

Here you go Rich...another winner.

That scares me less - particularly as I had a set of the tubulars (and loved them, FWIW), but also because it's quite a clean and sterile place with what looks to be one guy managing the whole process much more carefully, rather than a fairly carelessly executed step in a *massive* factory production line.

That said, maybe they'd have had less issues with their clinchers dismantling mid-ride if they weren't bonding what looks to be 5 wheels at a time...

[htwoopup]

To digress a little bit more what to do/is this a problem of the OP that @hugh posted...

Part of the reason that I went with a new very small wheel company on my last wheel purchase is that I visited them while they were making wheels. I loved their production process and their thought process. I asked the guy in Texas who knows carbon who was crafting a bike for me as I only know the production stuff in boats and he knows bikes and he said he knew the process and it was good. They wouldn't let me photo while they were doing and this doesn't show some parts of how they do it but I liked the concept and loved the wheels (although I will say they are at times tough but doable to mount certain tires on). BTW, this is the company that called me and said they had been supplied resin that was not 100% up to spec so they were immediately replacing my wheels which I think is more quick and pro-active and admirable than I have seen from others in the space...

https://www.falconcomposites.com/en/tech#en/technology

[zachateseverything]

I am a total layman and I can't watch that and criticise methods - BUT, there is absolutely *nothing* about that video that gives me any confidence in a carbon bike out of a Giant factory, or any other factory that uses similar methods. Even I can see from that how easy it would be for voids to be created, as Luescher Teknik often finds when he cuts bikes up. Yowsers.

I'm not sure what you're expecting. They're handlaying fabrics over a bladder which will then expand and push the fabrics tight against the mold and in the preferred orientation. Smaller sections of the frame then get glued together. It's pretty typical inside and outside of the cycling industry.

[RichTheRoadie]

I'm not sure what you're expecting. They're handlaying fabrics over a bladder which will then expand and push the fabrics tight against the mold and in the preferred orientation. Smaller sections of the frame then get glued together. It's pretty typical inside and outside of the cycling industry.

I'm not expecting anything, or believing it is not typical of carbon mass production - I'm simply saying that the process gives me no confidence in the absolute quality of a mass produced carbon frame; and that it makes it easy to see how voids in the carbon can occur.

[zachateseverything]

I'm not expecting anything, or believing it is not typical of carbon mass production - I'm simply saying that the process gives me no confidence in the absolute quality of a mass produced carbon frame; and that it makes it easy to see how voids in the carbon can occur.

you absolutely shouldn't ride a bike or drive a car then. tires are built basically the same way.