Yet another reason to avoid carbon frames

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peetee
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Yet another reason to avoid carbon frames

Postby peetee » 14 Aug 2020, 9:06pm

I know there are thousands out there proving to be trouble-free for their owners but I’m afraid with the sort of issues I have been asked to sort over the years I can’t help but see them as ticking time-bombs.
Take this one for example; not the first creaking Specialized frame I have been given. This two year old carbon frame has non-removeable factory-fitted aluminium inserts bonded into the frame to take a standard threaded hollow tech bracket. After satisfying myself that the crank and cups were in good order and fitted correctly I paid closer attention to the inserts and found that they have or rather, should have, a thin lip that overlaps the carbon shell. This lip is in the order of 1-2mm deep and in my opinion totally inadequate for its purpose which is, I can only assume, to prevent the shell from being inserted too far during production. It’s worth adding now that the external diameter of the BB cups is smaller than the cracked radius so over tightening of the cups is unlikely to have contributed. heavy handed use of a cup spanner may prove a risk but these bearings regularly expire and the tools are difficult to use in a perfect rotational plane so to have something so vulnerable there is poor design. This frame is on its original cups so if a spanner monkey is to blame he/she was a Specialized employee. The fractures appear to be very rough as if corrosion had hastened their onset. I would speculate too that this sort of damage could also come about if the chain is derailed. No sign of that on this particular frame which also showed the broken lip on the non-drive side. What exactly caused this I can’t say but the rider is a powerful guy who does ride out of the saddle a lot. I do wonder if frame flex was enough to force these lips away. I believe the loss of these lips has exposed the interface between carbon/resin and aluminium allowing moisture to compromise the joint and cause the creak.
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Last edited by peetee on 15 Aug 2020, 3:04pm, edited 3 times in total.
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JohnW
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Re: Yet another reason to avoid carbon frames

Postby JohnW » 14 Aug 2020, 10:02pm

petee - I'm an enthusiast for steel - I've only ever had (since I could afford them, anyway and thats 50 years or more) handbuilt steel frames.
In the last 30 years or so, the other materials have become increasingly popular, for whatever reason.

What I've seen of frames of other materials - and this is other peoples' experiences, of course - steel will remain my choice, and remains my favourite. The problem that you're highlighting, only serves to support my preference.

However, from what you say I have to wonder whether the design and detailing are the problem with the example you give - I'm not sure whether the problems are inherent in the material. I'm not a knowledgeable chap, and those who know the facts will be able to enlighten me/us.

I'm not standing up for carbon here - steel, for so many reasons, will be my choice.

What problems are inherent in carbon? to persuade those (who are seeking) to choose steel. I occasionally see a 1920s lug-built frame which is in almost day-to day use - but not with the original owner.

peetee
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Re: Yet another reason to avoid carbon frames

Postby peetee » 14 Aug 2020, 10:36pm

I see where you are coming from and your answer shows I have missed a vital point in my description. Threaded sections of the sort needed for bottom brackets cannot be reliably formed in carbon frames so metal sleeves are inserted to allow this. It is the bond between these two quite different materials that has the potential to cause problems which, I believe, is often a result of differences in the way the adjacent materials flex when forces are applied.
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djnotts
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Re: Yet another reason to avoid carbon frames

Postby djnotts » 15 Aug 2020, 7:18am

Surely on average a carbon will last say 3 - 5 years of "normal" use by a "normal" rider? Long enough to make the benefits of lightness and comfort the deciding factor. Given the financial means (which clearly many have) I would have nothing else.
Few want to keep same bike(s) for years. My one carbon is a delight. Wish I could afford for the other 4 bikes to be in same material (and for carbon touring frames to be more readily available at any price!).

Cyril Haearn
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Re: Yet another reason to avoid carbon frames

Postby Cyril Haearn » 15 Aug 2020, 8:18am

Not used a ludicrously light carbon frame, do not want to
I understand they can suddenly fail in various ways
Durability should be a property of cycle frames, 20 years at least
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philvantwo
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Re: Yet another reason to avoid carbon frames

Postby philvantwo » 15 Aug 2020, 8:19am

Don't think I'll be buying another carbon frame, mines a Dolan with an insert for a threaded BB, I bought it to replace a 6 year old Ribble aluminium frame that cracked on the rear drop out and was un-repairable. Yes the Dolans light but when I get up out of the saddle the BB creaks like mad. My other bike I use in the summer is a Brian Rourke frame, about 15years old now but never seen any rain and it's a joy to ride since I fitted a new 105 groupset to replace a crappy campag one 2 years ago. Nice solid frame and finished in the colour I chose, steel forks as well. Made in Stoke, UK!!

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Sweep
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Re: Yet another reason to avoid carbon frames

Postby Sweep » 15 Aug 2020, 8:47am

djnotts wrote:Surely on average a carbon will last say 3 - 5 years of "normal" use by a "normal" rider? Long enough to make the benefits of lightness and comfort the deciding factor. Given the financial means (which clearly many have) I would have nothing else.
Few want to keep same bike(s) for years. My one carbon is a delight. Wish I could afford for the other 4 bikes to be in same material (and for carbon touring frames to be more readily available at any price!).

3-5 years life for a frame! sod that. I've got still working components way older than that.
Why on earth would anyone want a carbon touring bike?
Sweep

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Sweep
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Re: Yet another reason to avoid carbon frames

Postby Sweep » 15 Aug 2020, 8:48am

peetee wrote:I know there are thousands out there proving to be trouble-free for their owners but I’m afraid with the sort of issues I have been asked to sort over the years I can’t help but see them as ticking time-bombs.

Out of interest peete, when you say you've been asked to sort out lots, can you say on what basis?
Do you run a bike shop/mechanics?

I'm no engineer and not very technical but I don't trust anything with inserts I have to screw into. Tiddly problem in comparison to the above, but I have had issues with inserts in an ally frame for bottle/mudguard mounts.
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peetee
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Re: Yet another reason to avoid carbon frames

Postby peetee » 15 Aug 2020, 9:37am

Sweep wrote:
peetee wrote:I know there are thousands out there proving to be trouble-free for their owners but I’m afraid with the sort of issues I have been asked to sort over the years I can’t help but see them as ticking time-bombs.

Out of interest peete, when you say you've been asked to sort out lots, can you say on what basis?
Do you run a bike shop/mechanics?
.

Yes I do. Now only on a part-time basis.
With this sort of problem it’s usual for the customer to expect it to be a mechanical issue that can be fixed. I have seen cases where the bike has already been to another mechanic and they have just squirted it with lube to make the noise go away (for a while) and charged the customer. If I can’t fix it I don’t charge and if I see something like this I leave well alone and advise the owner to return the bike to the retailer (Sometimes with a personally written report) and stand their ground till something is done.
Last edited by peetee on 15 Aug 2020, 9:48am, edited 1 time in total.
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reohn2
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Re: Yet another reason to avoid carbon frames

Postby reohn2 » 15 Aug 2020, 9:40am

djnotts wrote:Surely on average a carbon will last say 3 - 5 years of "normal" use by a "normal" rider? Long enough to make the benefits of lightness and comfort the deciding factor. Given the financial means (which clearly many have) I would have nothing else.
Few want to keep same bike(s) for years. My one carbon is a delight. Wish I could afford for the other 4 bikes to be in same material (and for carbon touring frames to be more readily available at any price!).

In the cyle touring world I strongly suspect you're in a small minority with that view.

The failure of CF in the rough and tumble of everyday utility and touring use is it's inability to absorb shock in everyday knocks and scrapes such as where an alu or steel frame may dent in say a crash or fall a CF will be rendered scrap.
Add to that the breakdown of bonding with other materials such as aluminium and steel due to differential material expansion and contraction in extreme weather conditions along road salt etc and you have a frameset that won't go the distance be that time or miles.
Anytime now there'll be others along in an attempt to discredit what is so obvious to the rest of the touring fraternity.
Last edited by reohn2 on 15 Aug 2020, 9:53am, edited 1 time in total.
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djnotts
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Re: Yet another reason to avoid carbon frames

Postby djnotts » 15 Aug 2020, 9:53am

Why would anyone WANT a bike that lasts for years? I just get bored. By carbon touring what I really mean is big tyres and mudguards! A grand a year depreciation is neither here nor there.

reohn2
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Re: Yet another reason to avoid carbon frames

Postby reohn2 » 15 Aug 2020, 9:58am

djnotts wrote:Why would anyone WANT a bike that lasts for years?

Why wouldn't they?

I just get bored... ..... A grand a year depreciation is neither here nor there.

It's your money.


By carbon touring what I really mean is big tyres and mudguards!

Because there's far more to a decent touring bike than big tyres and mudguards not least reliability,see my previous post.
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peetee
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Re: Yet another reason to avoid carbon frames

Postby peetee » 15 Aug 2020, 10:26am

djnotts wrote:Why would anyone WANT a bike that lasts for years? I just get bored. By carbon touring what I really mean is big tyres and mudguards! A grand a year depreciation is neither here nor there.

:shock:
I Know that wasn’t directed at me but I can’t let it pass.
I have never spent so much on a bike and rarely more on a car. I take pride in what I own and it is kept in good order and is presentable and reliable even if it is, by your quantification, ‘cheap’. Spending a grand on anything is a big deal in my book, let alone turning a blind eye to a burning away a grand.
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Sweep
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Re: Yet another reason to avoid carbon frames

Postby Sweep » 15 Aug 2020, 10:55am

djnotts wrote:Why would anyone WANT a bike that lasts for years? I just get bored.

...
! A grand a year depreciation is neither here nor there.


takes all sorts.

I look forward to your bike sale posts.

(but not the carbon ones)
Sweep

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Navara
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Re: Yet another reason to avoid carbon frames

Postby Navara » 15 Aug 2020, 11:08am

Cyril Haearn wrote:Not used a ludicrously light carbon frame, do not want to
I understand they can suddenly fail in various ways

Anything can suddenly fail in various ways.Almost everyone I ride with and have ridden with over the last 6 or 7 years ride carbon bikes.I don't recall any failures.I would really like to know the exact failure percentage compared to numbers sold?

djnotts wrote:Surely on average a carbon will last say 3 - 5 years of "normal" use by a "normal" rider? Long enough to make the benefits of lightness and comfort the deciding factor. Given the financial means (which clearly many have) I would have nothing else.

My carbon bike is 5 years old without a mark on it.I like carbon.There are some truly beautiful carbon bikes out there now.I think there is a lot of misunderstanding and hearsay regarding the durability.I had a carbon MTB that was abused like any MTB for two years,DH,XC,Trail,jumps and it survived it all.It should do that's what is was made to do :wink: It was scuffed and scratched as much as any Aluminum MTB I've ever owned.I'd have another tomorrow!
The only issue I have with certain carbon bikes(mine included) is that many go for press-fit BBs.Personal choice but I don't like them.

I think many who knock carbon bikes do so without any real world experience.Some people don't like modern bikes full-stop.Some don't like Allu bikes.There are cyclists out there who like the old fashioned curved forks and skinny steel frames,even on a new bike,they are never going to like an aero carbon bike.What some see as a natural progression in technology others see as heresy :lol:
I used to replace MTBs every two years,so one year I'd build a new HT,the next I'd build a new FS and so on for no other reason than change and newer designs.Road bikes I tend to replace every 3-5 years for the same reason plus they get less abuse.
Last edited by Navara on 15 Aug 2020, 11:10am, edited 1 time in total.