Are carbon frames strong enough?

[Streddaz]

Carbon's very risky in resale, because it can be hiding damage that's not visible to the naked eye.

Carbon products tend to cost 50% more than their aluminum alternative (e.g. $2k alloy frame, $3k carbon frame).

Carbon tends to only be strong in one direction, and relatively susceptible to impact damage.

Designing frames to do well in those lab tests is akin to teaching kids to just pass tests in school. The real world effectiveness is quite questionable. Some might be doing just fine out there, but the people who pick these half-baked things up might end up frustrated that they're being burdened with the prototype nature of these experiments or whatever.

I'd rather stick to the mainstream-enthusiast level, rather than throw money at some "heirloom" quality thing that promises that its quality is so good that it will last through multiple builds or whatever. Stuff gets outdated in the ebike world faster than the rest of the mtb industry, and the mtb industry sure does a good job of making people want to refresh their bike every 2-4 years.

For starters the difference between $2k and $3k isn't 50% that would be $4K and they aren't that much more expensive. The higher spec components are a much bigger price difference than the frame.
For instance the Nukeproof Mega frame is 38% more in the carbon frame version.

Also bike manufacturers do real world testing as well as lab testing and carbon frame mountain bikes have been mainstream for over a decade. Santa Cruz make some of the best mountain bikes in the world so to say they are half baked is pretty ignorant of what goes into the design and testing of a new bike.

 

[steve_sordy]

For starters the difference between $2k and $3k isn't 50% that would be $4K .....................

Someone needs to do their sums.
50% (ie half) more than $2k is another $1k which makes $3k in total. @Varaxis is correct.

The only way $4k comes into the equation is if you start with $4k and ask what is 50% of that.

 

[ebsocalmtb]

Frame material isn't an indicator of durability, that's more down to a specific brand in my experience. I have my own anecdotal experience breaking many frames... I've broken just as many aluminum frames as I have carbon frames. (3 of each) In my own experience with my own frame breakages and those in my riding crew, there is no impact that would have killed a carbon frame that wouldn't kill an alloy frame as a general rule... damage happens in the same types of events and the same types of rates.

What's more important is how overbuilt a given company is making a frame. For example, I have an SC megatower CC frame and a giant trance advance 29 pro frame. I can flex the giant frame with my fingers if I pinch the top tube. I haven't broken this frame (although I have broken other giant carbon frames) but I have sent both of these bikes cartwheeling down 20 degree grades on more then one occasion. My santacruz, is a brick shithouse and not only does it feel stronger by touch, I have done terrible things to it... things that would and have killed aluminum frame bikes in the past. It is built very differently then my trance 29. Even the sounds the bike makes while riding it, is different. I can feel the rear triangle flexing under load on the trance, where the santacruz feels like it's carved from diamond while riding it.

Also as a comparison, compare how orbea, giant and scott build their hydroformed bikes vs transition, privateer or raw. Also, as another aside... I love santacruz carbon frames but I would absolutely not buy one of their aluminum bikes. Their aluminum bikes are built rather clunky imo and feel appreciably different then their carbon counterparts, despite being heavy as hell. In contrast, transition builds an overly built, heavy alloy bike, that's genuinely indestructible and worth schlepping weight around.

The short story is that it's the bike mfg and how they build the bikes that matter. Hydroforming aluminum allows very thin walled aluminum that is just as fragile as a carbon frame. Don't assume that just because a frame is AL that it's going to be more durable for you. What's more important, is how you treat bikes generally. If you are careless, crash a lot and clumsy with your bike, get an aluminum bike, because you will be safe from the freak carbon frame puncture that can happen if it hits just right. But make sure you buy an aluminum bike from the right mfg that knows what they are doing with the proper specification, quality and qa/qc. Not all bikes are made with equal quality.

 

[cozzy]

Why were you worried about the carbon bike? genuinely interested....I mean what made you think you should be worried, because I dont give it a second thought?

I've had various carbon bikes and dont worry about them any more than the alloy bikes I've had. The carbon bikes have been crashed, dropped, had massive rocks bounce off the downtube , and generally treated the same as the alloy bikes, and they've been fine.

I've had 2 alloy bikes and 3 carbon bikes . The carbon bikes have not failed in any way. One aluminium bike cracked on a weld, the other got dented by a rock but I carried on riding it for a couple of years .

Through videos like this at around 9.50

Not a big crash. Splintered carbon bike due to rock damage.
Would have been a gouge or dent with alloy.
If people love their carbon frames that's great. Personally I will never own one again.

 

[ilostmypassword]

I had to check the date of the original post, this feels like a thread from the 2000’s. Lol.

There’s nothing inherently inferior about an aluminum frame, especially on an ebike where weight is basically a non-issue. But it’s not stronger or more durable than a carbon frame. I can’t believe in 2022 there are people who still believe that carbon frames are fragile or prone to failure. The material is very tough.

Regardless, carbon bikes do not fair well when they hit hard sharp edges. Yes this has been and will continue to be the case 2000 - end of time

 

[Alexbn921]

Frame material isn't an indicator of durability, that's more down to a specific brand in my experience. I have my own anecdotal experience breaking many frames... I've broken just as many aluminum frames as I have carbon frames. (3 of each) In my own experience with my own frame breakages and those in my riding crew, there is no impact that would have killed a carbon frame that wouldn't kill an alloy frame as a general rule... damage happens in the same types of events and the same types of rates.

What's more important is how overbuilt a given company is making a frame. For example, I have an SC megatower CC frame and a giant trance advance 29 pro frame. I can flex the giant frame with my fingers if I pinch the top tube. I haven't broken this frame (although I have broken other giant carbon frames) but I have sent both of these bikes cartwheeling down 20 degree grades on more then one occasion. My santacruz, is a brick shithouse and not only does it feel stronger by touch, I have done terrible things to it... things that would and have killed aluminum frame bikes in the past. It is built very differently then my trance 29. Even the sounds the bike makes while riding it, is different. I can feel the rear triangle flexing under load on the trance, where the santacruz feels like it's carved from diamond while riding it.

Also as a comparison, compare how orbea, giant and scott build their hydroformed bikes vs transition, privateer or raw. Also, as another aside... I love santacruz carbon frames but I would absolutely not buy one of their aluminum bikes. Their aluminum bikes are built rather clunky imo and feel appreciably different then their carbon counterparts, despite being heavy as hell. In contrast, transition builds an overly built, heavy alloy bike, that's genuinely indestructible and worth schlepping weight around.

The short story is that it's the bike mfg and how they build the bikes that matter. Hydroforming aluminum allows very thin walled aluminum that is just as fragile as a carbon frame. Don't assume that just because a frame is AL that it's going to be more durable for you. What's more important, is how you treat bikes generally. If you are careless, crash a lot and clumsy with your bike, get an aluminum bike, because you will be safe from the freak carbon frame puncture that can happen if it hits just right. But make sure you buy an aluminum bike from the right mfg that knows what they are doing with the proper specification, quality and qa/qc. Not all bikes are made with equal quality.

This
Carbon is just a material and as a frame choice is a very good one. I ran into the Pro Scoot rider after my buddy broke his Scott frame and he said he breaks them all the time. I've broken aluminum, but not Carbon. All my analog bikes will always be carbon as the weight matters. I prefer aluminum on my ebikes as it transfers heat better and I don't care about the weight savings.

As a side note, carbon is way easier to repair. Aluminum needs heat treated after welding.

 

[Growmac]

Come on.........you buy a car and dont understand any of the spec? You buy a sat nav and do not understand the spec? You buy endless components for a bike.........bars, suspension, brakes and you do not understand any of the spec? Yet you are happy to pay a premium of £2k because it says the frame is made of carbon...and thats it!!! Carbon fibre composites are hardly anything new!

No, I'm questioning whether there could be a spec that could meaningfully influence a buying decision. I know if a car is diesel or petrol. I know if it's turbocharged, and what the peak power per displacement is. I have an idea on economy. I happen to know details like whether it's direct or port injected.

Would I have an opinion on the precise specification and implementation of the crash protection? The type of explosive used in the airbags, and the parameters for their deployment? No. I trust the manufacturer to be on top of that sort of detail. And the precise type, layup, and general design of carbon fibre seems to me to be so potentially complex as to render useful specification to the end customer unlikely.

I could be wrong though, I would certainly be interested to know!

 

[Binhill1]

I had play in headset due to wear in carbon on a levo expert. Probably pilot error we will never know. Couldn't be repaired I was told so got new frame on warranty. Saying that I broke two aluminium frames .

 

[Nick314]

Cube Stereo Hybrid 140 HPC here - carbon main frame and alloy rear triangle.
I believe I'm a little bit over the weight limit when geared up, have thrown it through everything, including doing some very silly jumps at Leeds Bike Park and Dalby Forest, not a single issue and it's done 1500miles now

I think most of the carbon cracks on emtb's I've seen on here have been a manufacturing problem, if it concerns you just grab a 2nd hand bike, if it's not cracked in the first 6 months at least you know it's not a design issue or manufacturing fault.

Same with me - 1,600 miles and no issues. I live on the Sugar Loaf in Wales so it gets well worked too.

 

[Savan]

Specialized also has a lifetime warranty for frames

 

[Manc44]

The reason carbon is used for road frames is to save weight and reduce road vibrations on those silly 23mm tyres they use.

If you're using a full suspension eBike, who cares about road buzz or bumps when you've got suspension and who cares about the weight saving of ~3lb on a carbon frame when the bike weighs 55lb+ anyway and you can have a motor helping you anytime.

I do ride a carbon hardtail eBike but it's on the road and I don't really fit in with the discipline in the way most of you guys probably do.

If you're leathering a bike around trails and these companies will do a lifetime warranty on aluminium frames but not carbon, I'd probably never bother with a carbon one for that application. The only reason my hardtail is carbon is, it was the only hardtail donor frame I had at the time, I'd rather it was aluminium and I'm just pootling around on the roads.

 

[Mikerb]

No, I'm questioning whether there could be a spec that could meaningfully influence a buying decision. I know if a car is diesel or petrol. I know if it's turbocharged, and what the peak power per displacement is. I have an idea on economy. I happen to know details like whether it's direct or port injected.

Would I have an opinion on the precise specification and implementation of the crash protection? The type of explosive used in the airbags, and the parameters for their deployment? No. I trust the manufacturer to be on top of that sort of detail. And the precise type, layup, and general design of carbon fibre seems to me to be so potentially complex as to render useful specification to the end customer unlikely.

I could be wrong though, I would certainly be interested to know!

It is common place in the windsurfing and surfing industry for brands to fully explain the spec of composite items like boards, masts, booms......on their websites. Some of that spec is also an integral part of product descriptions. Its nothing difficult to grasp!! I see no reason why bike brands should not do the same. Invariably they just give their particular fabrication process a name...and that applies to both ally and carbon frames.......its meaningless......and to some extent the brands that are doing a good job with both constructions are doing themselves a disservice compared to their competitors.
I have bought and used carbon composite windsurfing components for decades. Its nothing new!!

 

[Pdoz]

It is common place in the windsurfing and surfing industry for brands to fully explain the spec of composite items like boards, masts, booms......on their websites. Some of that spec is also an integral part of product descriptions. Its nothing difficult to grasp!! I see no reason why bike brands should not do the same. Invariably they just give their particular fabrication process a name...and that applies to both ally and carbon frames.......its meaningless......and to some extent the brands that are doing a good job with both constructions are doing themselves a disservice compared to their competitors.
I have bought and used carbon composite windsurfing components for decades. Its nothing new!!

I thought most of the brands get their frames built for them at the same factory as their competitor, but to the specification they have worked out? Surely they would be handing out " trade secrets" to the opposition? They'd also he losing some of the marketing edge - anyone can ask for the same materials to be used, the magic is WHERE to use them ( I'm thinking tapered masts and high roach sails now)

 

[ilostmypassword]

It is common place in the windsurfing and surfing industry for brands to fully explain the spec of composite items like boards, masts, booms......on their websites. Some of that spec is also an integral part of product descriptions. Its nothing difficult to grasp!! I see no reason why bike brands should not do the same. Invariably they just give their particular fabrication process a name...and that applies to both ally and carbon frames.......its meaningless......and to some extent the brands that are doing a good job with both constructions are doing themselves a disservice compared to their competitors.
I have bought and used carbon composite windsurfing components for decades. Its nothing new!!

It’s hitting water though not rocks

 

[PenSki]

Can all those reading this thread, who have broken a CF MTB frame, please come forward now and tell us your story of carbon misery, because all I seem to see written about is Al frames fatigue cracking.

 

[KnollyBro]

My wife backed over her friends carbon framed bike after a grueling ride. They all just assumed that my wife was going to load up all the bikes onto the bike rack. The rear triangle snapped in half. The aluminum wheel was ok!

 

[Pdoz]

My wife backed over her friends carbon framed bike after a grueling ride. They all just assumed that my wife was going to load up all the bikes onto the bike rack. The rear triangle snapped in half. The aluminum wheel was ok!

Are you intending to introduce the concept that carbon bike OWNERS might be part of the issue?

 

[Endoguru]

Alloy frames crack as well. Look up Paul Aston discussing all the cracked frames from Commencal. I’m not a Commencal hater. They have the best DH bike I’ve ever ridden. Just saying all bikes can fail if ridden hard enough. Or stupid enough in my case.

 

[Binhill1]

I broke two alloy frames non electric .Marin Mount vision and a Rocky Mountain both high spec frames , not doing anything serious both replaced under warranty. Both went just next to weld which is always the weak point I am told. Wear in Levo carbon frame at headset so got new frame warranty again

 

[BeBiker]

Most people here advocating against carbon - pro alu or against alu - pro carbon, need a 5mm thick steel frame I think.

 

[Binhill1]

Most people here advocating against carbon - pro alu or against alu - pro carbon, need a 5mm thick steel frame I think.

Well my 25 year old custom built Alves Reynolds steel framed hardtail is still going strong . Campagnolia cantilever brakes as well .

 

[Daev]

I'm crap techically, tank through everything, had 3 cf and never had a problem

 

[Mikerb]

It’s hitting water though not rocks

........so you think water is soft when travelling over chop at 30 knots plus?..............or landing a jump..........or getting caught in a wave barrel?? Methinks you are no seafarer!!

 

[Binhill1]

........so you think water is soft when travelling over chop at 30 knots plus?..............or landing a jump..........or getting caught in a wave barrel?? Methinks you are no seafarer!!

Hard as rock water if you hit it right or wrong .

 

[Streddaz]

My wife backed over her friends carbon framed bike after a grueling ride. They all just assumed that my wife was going to load up all the bikes onto the bike rack. The rear triangle snapped in half. The aluminum wheel was ok!

I'm sure an aluminium frame would have broke too if you had driven over it

 

[KnollyBro]

I'm sure an aluminium frame would have broke too if you had driven over it

I hope no one ever finds out! I have also had 10+ aluminum mtbs and only 2 carbon mtbs and the only thing that I know for sure is that CF will end up in a landfill and AL can be recycled. Other than that, at my age and skill level, I have yet to notice a difference except in my bank account

 

[Daev]

I hope no one ever finds out! I have also had 10+ aluminum mtbs and only 2 carbon mtbs and the only thing that I know for sure is that CF will end up in a landfill and AL can be recycled. Other than that, at my age and skill level, I have yet to notice a difference except in my bank account

Need to be a bit more imaginative in the 'Re-use' category - arty garden installation ? Coat-hanger ? Distraction / trap for bike thieves ? .... The list is endless

 

[steve_sordy]

Need to be a bit more imaginative in the 'Re-use' category - arty garden installation ? Coat-hanger ? Distraction / trap for bike thieves ? .... The list is endless

A friend of a friend hangs his frame on the wall. He is single of course.

 

[Zimmerframe]

A friend of a friend hangs his frame on the wall. He is single of course.

I hear @BAMBAMODA hangs his girlfriends on the wall .. he is normally single of course.... and often looking for plasterers .

 

[steve_sordy]

I hear @BAMBAMODA hangs his girlfriends on the wall .. he is normally single of course.... and often looking for plasterers .

Are you sure he doesn't mount them on the wall? That's a whole different thing!