I hate carbon

2WheelsNot4

E*POWAH Master
Oct 17, 2021
917
712
Scotland
Never really looked upon it as a material you should be building an MTB out of

Sure I've heard the argument that F1 superduper racing machines use it, but those guys have millions to spend, and can replace any part even after a single race.

Bikes get scraped, and i feel that lets moisture inot the layers. Plus its not so strong it doesnt crack or break or anything like that and when it does(or if rather) then the replacement cost is rather spendy.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
9,098
9,586
Lincolnshire, UK
@2WheelsNot4 Here is a 6 min vid of Santa Cruz testing of a carbon frame.


If you want to go straight to the "Official Pinkbike Swing-A-Carbon-Frame-Into-A-Concrete-Block Test" then go to the 5.00 point.
Prepare to be amazed. :ROFLMAO:

Edit: link attached.
 
Last edited:

volts

Active member
May 15, 2018
343
266
DK
I think the main problem with carbon is how they will end up as landfill when they done for. It's not smart.
Carbon as a material is fine. If you are one of those types who obsess about every little scratch on carbon, then carbon is just not for you and lucky for you there are other options like aluminium, steel and titanium.

Just get the material you like and if there is a material you don't like, try to avoid buying that particular material.
It really is that simple.
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,682
5,245
Coquitlam, BC
A nick or a scratch is certainly concerning on carbon material. If the fiber’s are exposed, immediate attention or repair is necessary. My Trek Rail is carbon and after a crash or impact I must inspect the bike for any potential damage. If it’s beyond repair then it’s garbage and the part needs replacing. Some repairs may be possible, otherwise it’s garbage.

I don’t know if carbon fibre is recyclable. Alloy or titanium probably is and graphene has other issues ($$$).

Back in the day (👴), I used carbon arrows for competitive archery (Beaman/Easton). They were light and strong. But if they suffered a very small scratch they were likely destroyed. Flexing a carbon arrow before every shot was absolutely necessary. If you heard a slight creaking noise …don’t shoot it, period. Or else! I’ve only seen pictures of a shattered carbon arrow imbedded in a hand. 🤮.

That carbon is likely in a landfill somewhere…forever.
 

MOTO13

Active member
Sep 16, 2020
337
385
Elkhorn, Wi
Don't crash a carbon framed bike...ever. If you do, always sacrifice yourself and save the bike.
Problem solved...you're welcome.

I prefer the feel and ride sound of carbon over aluminum. Carbon just feels better to me in every way. That being said, if they completely did away with carbon frames, I'd be fine with aluminum. But, I want my carbon bars.
 

jimbob

Active member
Aug 3, 2020
526
433
East UK
So, to someone who's never ridden a carbon bike, what are the advantages over alu? Weight, I imagine, but that can't be much of an issue for an Emtb?

I've heard people talk about ride feel, but is there really a difference?
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,628
5,104
Weymouth
I have used carbon components extensively for windsurfing. The best masts and booms are 100% carbon and high end boards are either all carbon or a mix of carbon and other composite layers like australian pine or bamboo. There is a very good reason for the use of carbon in each of those components. A mast needs to be light and able to flex but more importantly needs to return to shape quickly ( fast reflex). A high modulus carbon achieves that. A boom needs to be light but to resist flex and retain its shape. Again carbon enables that. A mix of UD carbon ( unidirectionally very stiff) and matrix carbon ( stronger but less stiff and resists flex at different angles) is used for board construction ( UD on the hull/matrix on the deck). All of those components are immensely strong for their intended use but all need special care, especially against single point impact. So a 100% high modulus mast costing over £1k can be bent to ridiculous angles without breaking, yet drop it on rock strewn beach and it is likely toast! Carbon boards can be repaired ( by an expert), masts and booms cannot.

I mention all of that because for each of those components....in that sport....I know the type and modulus of carbon used, the type of resin used, the composite process ( pre preg/wet/ composite layup), what factory with what reputation fabricated the component etc.

Anyone seen any of that information regarding a "carbon" bike frame?? It is not even specified if it is 100% carbon or a composite consisting other materials as well..............glass, kevlar etc.

Kevlar for example provides significant impact resistance but is difficult to integrate into a composite layup and heavier than even a matrix carbon so usually only used sparingly in highly vulnerable areas ( on a windsurfing board at the very end of the nose for example) .

Ever wondered why some brands ( e.g Cube) seem to be a ble to fabricate "carbon" frames at significantly less cost than others?

Without full disclosure of the fabrication process I would not buy a "carbon" framed bike...............and unless I could see how the inevitable , even minor, impact damage was ameliorated in the design I would not consider carbon a suitable material for MTB/EMTB frame construction. For road bikes where stiffness and weight are primary consideration, and impact damage far less likely, I see the rationale..........but would still want to know what I am being asked to pay for!!
 

Ark

Active member
Mar 8, 2023
464
391
Newcastle Upon Tyne
So, to someone who's never ridden a carbon bike, what are the advantages over alu?
the weights usually only around 1.5kg lighter than aluminium.. total pointless just something rich people can spend money on to feel elite.
but oh it's stiffer than aluminium.... if aluminium wasn't stiff the paint would crack from the frame flexing.

but but it's so much stiffer you can put out 1watt more energy!

@2WheelsNot4 Here is a 6 min vid of Santa Cruz testing of a carbon frame.


If you want to go straight to the "Official Pinkbike Swing-A-Carbon-Frame-Into-A-Concrete-Block Test" then go to the 5.00 point.
Prepare to be amazed. :ROFLMAO:

Edit: link attached.
do they do the test with the weight of a rider as well? if not it's pointless
 

Waynemarlow

E*POWAH Master
Dec 6, 2019
1,126
902
Bucks
but oh it's stiffer than aluminium.... if aluminium wasn't stiff the paint would crack from the frame flexing.
Aluminium skinned and ribbed aircraft are scrapped after a max duty cycle of about 1/5 of the equivalent carbon aircraft, I wonder why that is ?
 

FirstAscent

Member
Apr 5, 2023
104
141
Portland
I'm a huge fan of carbon! I've been running carbon frames for over 10 years including my full on DH bikes ridden all over Alaska crashing down mountain sides etc. Never had a single issue with any of my frames ever.
although I was never concerned about it, carbon is like anything other material in the sense that you can have good and bad designs or course. I've also used a lot of carbon parts including wheels on motorcycles too.

Carbon is an amazing material, and we are well far enough along that it's shown its capabilities and reliability.
Get carbon, ride it like any other bike and have a great time :)
 

A06

Member
Mar 9, 2023
106
85
Corona, CA
Way to many factors to account for to simply say one material is better than another. "Carbon Fiber" is used as a very generic term much like saying "Metal". When we discuss bike frames we typically assume aluminum 90% of the time and the other 10% we may introduce Ti or ChroMo into the discussion.

The composition of the carbon, the layup, the epoxies, the forming method and other factors contribute to the end strength and dynamic characteristics of whatever you are making.

One of the previous replies used archery as an example. Taking that path there are 3 good examples of what I'm referring to.

PSE, Bowtech and Hoyt all offer a carbon fiber riser compound bow. Bowtech uses recycled ground carbon fibers mixed with a polymer to create what is essentially a carbon reinforced plastic riser. There's more carbon than there is polymer so they are not lying by calling it a carbon bow. Hoyt uses an aluminum skeleton and carbon wraps it with a specific layup to produce the final dimensions but also to reinforce the aluminum skeleton and again the ratio of carbon to aluminum is higher so they call it a carbon bow. Lastly PSE uses foam core material and builds up the layers around the foam however the foam only serves to provide a form for the carbon and is not structurally important. So there's 3 examples of the same product utilizing carbon fiber but in very different ways.

I think its too broad of a subject to make generalized assumptions of the material application as manufacturers each have their "secret sauce" in their manufacturing processes when it comes to the bigger companies. I'm sure there are also companies which do the inhouse CAD work but then farm out production to Taiwan. Question then becomes how much direct oversight does that company have over the overseas production? Some companies probably make frequent visits and have tight QC while others simply may send the CAD files by email and say make a thousand frames based on the drawing.

As for sustainability yeah that's a concern but one which can be solved. Carbon can be recycled but there has to be a demand for the recycled material and it has to be an economical process for there to be an incentive to do so. Currently I don't feel either criteria is met but there was a time when that also held true for aluminum which I believe is the 4th most recycled material globally.
 

2WheelsNot4

E*POWAH Master
Oct 17, 2021
917
712
Scotland
I'm a huge fan of carbon! I've been running carbon frames for over 10 years including my full on DH bikes ridden all over Alaska crashing down mountain sides etc. Never had a single issue with any of my frames ever.
But do you accept that cracking and breakages do occur, or do you just think you've been really lucky and have received an unbreakable carbon frame.

I've ridden White bros forks for a long time, and had no problems, i even got them 2nd hand. But the truth of the matter is its not really the material designed for the most part for long term use ,in an environment where its going to suffer damage as part and parcel of the sport(or hobby, because thats really what it is)

Were it cheaper, then that would make it more acceptable for use in that it can be replaced without breaking the bank.

It is important to note that many bike manufacturers will have lifetime or long warranties on their frames, but only if they are made of steel or alloy and carbon is excluded. I think Kona for one has long held this clause in their warranties.

Im quite happy that if i drop my (alloy) bike and scrape, scratch or even dent the frame its going to be fine. Im not sure i could retain confidence due to the nature of the sudden catastrophic failure that carbon is known for. Especially if its involving speed, rocks and the like
 

A06

Member
Mar 9, 2023
106
85
Corona, CA
But do you accept that cracking and breakages do occur, or do you just think you've been really lucky and have received an unbreakable carbon frame.

I've ridden White bros forks for a long time, and had no problems, i even got them 2nd hand. But the truth of the matter is its not really the material designed for the most part for long term use ,in an environment where its going to suffer damage as part and parcel of the sport(or hobby, because thats really what it is)

Were it cheaper, then that would make it more acceptable for use in that it can be replaced without breaking the bank.

It is important to note that many bike manufacturers will have lifetime or long warranties on their frames, but only if they are made of steel or alloy and carbon is excluded. I think Kona for one has long held this clause in their warranties.

Im quite happy that if i drop my (alloy) bike and scrape, scratch or even dent the frame its going to be fine. Im not sure i could retain confidence due to the nature of the sudden catastrophic failure that carbon is known for. Especially if its involving speed, rocks and the like
Rocky Mountain 5 year on frames regardless of material. Intense 5 year on carbon they no longer offer Aluminum but 3 year on the carbon DH frames. Specialized and Giant are lifetime on either material. Kona lifetime for non carbon and 3 year on carbon. Santa Cruz is lifetime on all frames.

The odd one out is per your example Kona. So the reason behind that is unknown and drawing a conclusion that one material is superior to the other based on that is an assumption. Maybe they have a high failure rate due to poor QC. Maybe the cost of replacement of carbon vs a metal frame was the reason vs high failure rate.

Most DIY garage mechanics could patch/repair carbon at a superficial level with no real special equipment. Crack an aluminum weld and you better be a proficient TIG welder with a rig that has reverse freq capability. Even then most goons in their garage are clueless as to the heat control measures needed to maintain the material integrity. You ever hear someone say the metal will break before the weld? Thats because often the base metal is overheated and becomes brittle. Ideally the weld and base material should be structurally homogenous.

Lastly the loading of carbon is much more critical than it is with a metal frame. A heavy carbon eMTB shouldnt be put on a bike rack where its supported by the top tube. That structural member is not designed to be loaded from that direction (pulling up on the top tube) but rather is designed to take the dynamic loads of a rider and the trail which typicaly means loading the framework from the headtube and shock mounts/linkages.

For a true apples to apples comparison one would need to do an FEA on two identical dimensioned frames of both materials and account for all of the variables such as the weave of the carbon the layup orientation the resins etc for carbon and similar factors for the alloy frame. Again I think the scale of operation factors in heavily to how much R&D goes into this. A small boutique brand might not go to such extents or have the capability to do so. The bigger brands such as Specialized have the engineering power to do all of this which is probably why they have no problem offering a lifetime warranty...or the cost of replacement is insignificant at scale for them.

FWIW I had a Scott Scale 50 aluminum frame about 8 years ago which failed at the top of the rear triangle where it meets the seat post tube, cracked weld. I ground half the weld and stitched it back up no problem. Only owned 3 carbon frames and no issues so far.
 

Shjay

Well-known member
Apr 30, 2019
835
491
Kent
Was quite fun putting a carbon frame in a vice & crushing it. You could hear it splinter & would still spring back until totally damaged. Was warranty frames that if we didn’t people would try & dig out of skips & resell on eBay!!
 

wildsau2

Active member
Jul 6, 2018
167
123
Germany, Karlsruhe
on a roadbike or gravalbike or light xc mtb i go for carbon. its stiffer, great speed acceleration.
for eMTB i had carbon and aluminum in the past, i found that the motor is always louder on carbon frames - may be because of the stiffer material which produces more resonance?
so i prefer aluminum on eMTB
 

jimbob

Active member
Aug 3, 2020
526
433
East UK
I have to say, having read all of this thread, I still can't see why I should go for a carbon bike!
 

2WheelsNot4

E*POWAH Master
Oct 17, 2021
917
712
Scotland
Giant are lifetime on either material
If we use Giant as the example, they may have a 'lifetime' warranty, but there is clear indication that they wouldn't honour it.
So while its ok to offer such, actually getting it might not be as straight forward as it should be.
Do you own a carbon framed bike?
Are you new to the party or something ?. Thanks for the (slightly trolly) input
 

MOTO13

Active member
Sep 16, 2020
337
385
Elkhorn, Wi
I have to say, having read all of this thread, I still can't see why I should go for a carbon bike!
Ride a carbon and an aluminum emtb back to back...if you can't tell the difference, get whatever. I have done this many times on my bikes. To me, the difference was quite noticeable. Nothing that I'd freak out about, but there was a definite difference. The steering input, the ride difference, the sound...the bikes just "feel" different to me. Everything seems tighter on a carbon bike for some reason.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,628
5,104
Weymouth
The Giant warranty (for example) is for defects of material or workmanship...
the bike has to be assembled by and serviced by a Giant dealer and not be modified from original spec

.....seems like a few hoops to climb through for a successful warranty claim!!

Obviously the warranty does not cover impact damage or use of the bike beyond its specified/intended use..............you might be surprised what maximum drop or jump even some full suspension bikes are limited to in terms of those specifications!!

Personally I would not put much faith in warranties.
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,880
6,976
UK
Are you new to the party or something ?. Thanks for the (slightly trolly) input
Lovely. Reliable. 😂

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