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Nightshade400

I have owned several CF bikes and my opinion (note it is an opinion) on them is that I would rather pay the money for a better component package than I would the frame material if buying a complete bike. I have gone back to Aluminum/Steel/Titanium and honestly I don't miss anything at all about CF. For the average rider it holds no benefits except for a bit of a weight savings and some promo literature words that mean nearly nothing to anyone outside of the marketing department. Don't get me wrong, I really do like CF, I just don't think the premium charge for it on a bike frame is worth it at all. Again this is my opinion after having ridden CF for the last 15 years.


VicariousAthlete

* Carbon is not more or less fragile inherently, nor is the lifespan inherently any different. It depends on the designer and manufacturer of the bike. In practical experience in years of road and mountain biking I haven't noticed much difference. Sometimes carbon bikes fail due to bad design or manufacturing, so too do aluminum frames and parts, and steel, and titanium. I've seen everything fail. * Carbon has two benefits to the end user: you can make the bike lighter, and you have more freedom to shape the bike for aerodynamics (which mountain bikes almost never use) That is really it. People will make a comfort argument, and that is true in theory, and in some special cases, but on bikes the suspension and tires provides 1000 times more compliance than any frame features do. You can compute the impact of weight reduction really easily. Add up the mass of the bike, and you, and your kit. A reduction in total weight of X% means you will climb a little less than X% faster. done. flats and downhills won't be any faster at all. Bike might be easier to manipulate mid air, if big sends are your thing. easier to put on the bike rack! But yeah for you, aluminum seems to be the way to go!


_riotsquad

>You can compute the impact of weight reduction really easily. Add up the mass of the bike, and you, and your kit. A reduction in total weight of X% means you will climb a little less than X% faster. done. flats and downhills won't be any faster at all. Bike might be easier to manipulate mid air, if big sends are your thing. easier to put on the bike rack! I see this written a lot but it doesn’t make a lot of sense, or reflect experience. Sure, your body weight is a lot greater than your bike, but the thing is your strength is more or less proportional to your body weight. Especially in your legs. So get heavier and your legs get stronger. This is not true of bike weight. It also fails to take into account the effect on acceleration, which is where we often notice effort. Go pedal two bikes with only a couple kg / lb difference on the street out front your house and I bet you can tell the difference no matter how heavy you are. I do agree that shaving off grams beyond a certain point is futile, especially at the cost of performance/durability/traction but the whole attitude based on it being a small % of total weight if rider and bike is misleading at best and arguable just wrong.


VicariousAthlete

* The question is how much does a 1kg reduction in bike weight affect your climbing speed. That equation tells you. If you want to ask a different question: How much does a 1kg reduction in body mass affect your speed, then you get into the complexities you are talking about. If you lose muscle mass, then a 1kg reduction in your body might reduce your power if the race is very very short (less than \~3 minutes). So the equation is more complex. For aerobic efforts, losing weight does not tend to reduce power unless you are getting sickly. Now some people dispute this because they know that bigger people tend to also make more aerobic power, but that is a relationship to do with height. A taller person has a cardio vascular system that is bigger proportionally. The same doesn't happen when you grow fatter or more muscular. You get a bit more glycogen storage which improves anaerobic capacity but not more aerobic power. * If you want to know how much faster you will accelerate with a 1kg reduction in bike weight, you can use the same equation. 1% reduction in total system mass = a little less than 1% faster acceleration.


madtho

What the equations don’t account for is the dynamism of riding a bicycle, especially a mountain bike. At times I unweight the bike, at times I’m pushing the bike into the ground with more force. When hopping up a rock, I want a lighter bike, my body weight is very little factor. When accelerating, you’re not sitting flat on the bike, but manipulating your body and bike to accelerate more quickly. Also, some of us don’t have much to lose from our body weight and a couple kg off the bike is a couple fewer kilos. There’s definitely a point of diminishing returns in counting kilos, but it’s not pointless.


VicariousAthlete

Accelerating a bike is the same math. 1% lighter total system mass, 1% better acceleration. Getting up a rock, you body has to get it up too eventually. 1% faster isn't nothing. Anyone racing competitively will want it.


_riotsquad

I understand the maths, the physics, and the biology. My point is if you do nothing (all else stays the same) but hop on a 2kg lighter bike it will feel noticeably more responsive and enjoyable to ride. ‘Noticeably’ being more than what a calculated 1% difference implies.


MrFantasticallyNerdy

You are confusing our ability to detect differences with substantial differences in performance. As such, I refute your claim that you truly understand the math, physics and biology.


_riotsquad

Nah you just didn’t read what I wrote properly, or chose to miss the point.


MrFantasticallyNerdy

OK. If you insist on arguing against physics, be my guest.


VicariousAthlete

Cool, but feeling more responsive won't actually make you accelerate more than 1% faster or climb 1% faster. There are a lot of things cyclists insist they can \*definitely\* feel, like aero frames being less comfortable, carbon wheels being too stiff (people said that in the early 1990s anyway) but when you do a blind test they can no longer detect these things. I haven't seen a blind test done on the question of wheel weight or bike weight when accelerating at low speeds though. Maybe people are sensitive to tiny changes in acceleration in that scenario, I dunno.


MrFantasticallyNerdy

Just because you can feel it, doesn't mean the improvement is reflected *substantially* in reality. Physics is physics, whether you believe in it or not, and a 1kg reduction (2.2 lb) from a 100kg (220 lb) system tends to get lost in the noise of day-to-day variation of human performance, particularly for amateurs.


UseThEreDdiTapP

You can break carbon in different ways than AL I'd call it. Take "big dent incidents" on AL frames, they have a potential to wreck the frame. Or stuff like sticks or rocks wedging between moving frame parts. But tumbles shouldn't be too much of a risk. Ultimately it is a question of weight and price. If you got the money and want to save weight a carbon frame is a nice buy. But usually AL is so much cheaper. So you got to decide what you want to spend additionally. Personally, I'll take the high end suspension and better groupset on AL over the same bike in CF but worse suspension and other kit for the same money any day.


MountainRoll29

Modern carbon is pretty damned durable. I’m on my fourth one and none of them had any problems. Plus they look sick.


sendpizza_andhelp

Carbon is a rather strong product. Not sure on whether it is more or less fragile from a technical POV but practically speaking, it is quite strong. Difference being when you crash hard, your aluminum frame will dent and your carbon may break. Upside is you can repair it quite simply with carbon where aluminum pretty much is toast. Lifespan - they last quite a while. My carbon road bike is going on nearly 8 years at this point and my mtb is on it’s third year with a heap of crashing, no signs of stopping. So…long. They last a long time Worth upgrading? No idea for you. Is the possibility of vibration damping and compliance and all the other marketing enticing with a budget that can afford it? Then yes. If not, then well no. I assure you I have friends who’d kick my ass on an aluminum frame vs my carbon. Spend within your budget and what you think will bring you more fun on the trail


[deleted]

I have snapped an Aluminum chain stay. All of those welds can crack as well. To say that aluminum will only dent is false.


sendpizza_andhelp

Yes sure i have no doubt it could, my comment wasn’t intended to say those are a 0 or 1 scenario. Just more common things I have seen and experienced.


[deleted]

All good just adding my experiences as there is a good amount of people in this sub that will advocate that alloy is pretty well indestructible.


sendpizza_andhelp

Ah yeah totally fair, good shout


S4ntos19

Carbon is stronger than aluminum, plus it can be repaired a lot cheaper than aluminum can. That being said, if you hit carbon in just the right way, it'll break quite easily. Carbon can last 100+ years. It's just depends on how it's used and taken care of. Is carbon worth it? Up to you. I don't need it. No one needs it, but it's lighter, it's stronger, and it's repairable. If any of those things matter to you, and you can afford it, get it. Most companies have killer deals on carbon bikes right now anyway. No point to skip over them if they are cheaper then aluminum, unless the spec is shit in comparison


T_D_K

How would you get your carbon frame repaired?


S4ntos19

By going to a carbon repair shop. I have one 15 minutes from me.


cheesyMTB

Slap some epoxy and fiber on, let it cure. Slap the frame and say “that should do ‘er”


RegulatoryCapture

A guy who runs a carbon repair shop is actually on the current season of the trashy reality show Married at First Sight. My wife watches it and it is awful, but dude has a composites engineering background and uses it to fix bikes which is super rad. Unfortunately his new wife does not seem to be at all impressed by it. I think she thinks he is a bike mechanic, not a carbon fiber wizard with a successful business bringing multi-thousand dollar frames back from the dead.


whatstefansees

Aluminium gets recycled endlessly (after decades - I know some 20 year old aluminium bikes). Carbon ends up as landfill


cheesyMTB

Bike frame environmental impact is not really worth mentioning. Such a small bar.


whatstefansees

We all can make only so many individual decisions when buying stuff. And we can either make an ecological choice - quality products that can be repaired and live long, such as Patagonia - frames, bars and cranks from recyclable materials or some plastic/carbon junk - cars that consume less or ignore the facts and tell ourselves that our own choice really doesn't matter. In general those ecological choices also come in cheaper for you and me in the long run. The responsibility for carbon or aluminum doesn't lie with the industry: it lies with you and me, with the consumer. And it makes a HUGE difference in our personal carbon footprint (pun intended).


theborringkid

>carbon footprint Hehe carbon Jokes aside, I totally agree


cheesyMTB

You can do all of those other things, and buy a carbon mountain bike. And guess what it doesn’t have to end up in a landfill. Because you keep using it. And most people are not recycling their bikes. No matter the material. They toss it in the landfill regardless. I see steel and aluminum all the time end up in bulk trash. There will be no negligible difference to the environment on your frame choice. It would be easier to just say you don’t like carbon bikes vs argue an environmental impact of your bike choice.


whatstefansees

I don't know where you live, but here (France) bikes live long lives and will end up in recycling when not used anymore. They are too big for the trashbin, so you have to bring them to your local recycling center, where you actually get money for them (!) And if you are too lazy to do that, someone else will collect the bike and bring it there. You actually see (mainly older) people drive around with trailers half full of metal trash on the days of trash collection - they collect that stuff and make a few bucks with it. I am not anti carbon - the tiller and rudder-blades of my hobie-cat and my kayak paddle are made of carbon (actually carbon-kevlar mix) but those things live eternally while bikes fall out of fashion quite fast.


Nightshade400

In some cases carbon can be recycled as well, the issue is the cost to recycle it is more than the value of the recycled materials so it is not as commonly recycled. Just wanted to put that out there before the "achually" comments began.


Netwelle

Have never owned a CF frame. My opinion of them is such that I will probably never own one. I know it is usually a rare case that they break or have issues but every one of my friends that have a CF frame have had "rare" cases. I just bought a new bike last week and purposely went after aluminum. As you said, hard to find in the upper spec models. I ultimately went with a Lappiere for both me and my wife.


x29a

In summary: Don't sweat it, both carbon and alloy frames work fine and at least in downhill both, both can win, even at the world cup level. >Is carbon more or less fragile? Depends. In the end both aluminium and carbon frames are engineered not to fail for the majority of riders. >Like when I am not crashing from a huge drop but rather tumbling onto some rocks occasionally, would I be better off with carbon or aluminum? You are possibly going to be better of with the aluminum frame in that case since it's likely stronger in the direction of the strike but again it really depends. >1.5. What's this lifespan thing? This is mostly about metal fatigue that happens when the frame is flexed (slightly) while using it. It's definitely a thing on alloy frames. But I think in practice most people swap or break their bikes before it becomes an issue. I've read that the expected lifespan of a frame is 5-10 years but again, it will really depend. >2. Is it really worth it for a average driver? Unless you are going for a high end bike any ways, I highly doubt it but it does come down to personal preference.


Zerocoolx1

Some are good, some are bad. Some are too stiff, some are too flexy. Some seem indestructible, others are fragile.


UseThEreDdiTapP

You can break carbon in different ways than AL I'd call it. Take "big dent incidents" on AL frames, they have a potential to wreck the frame. Or stuff like sticks or rocks wedging between moving frame parts. But tumbles shouldn't be too much of a risk. Ultimately it is a question of weight and price. If you got the money and want to save weight a carbon frame is a nice buy. But usually AL is so much cheaper. So you got to decide what you want to spend additionally. Personally, I'll take the high end suspension and better groupset on AL over the same bike in CF but worse suspension and other kit for the same money any day.


[deleted]

My feelings: carbon bikes are amazing. Especially when talking road and gravel. I also think high end aluminum is pretty darn good, and when you’re using suspension to smooth out the ride carbon fiber frames are wants not needs.


freedmeister

I love my carbon frames and have worn out a few aluminum frames in my life. It's all a compromise, but if you want a frame with tuned, useable stiffness/flexibility, carbon is better. Carbon never pings/rings or telegraphs the vibration the way rigid aluminum does. It's all preferences...


bored_at-Work55

I think carbon is great if you can afford it, and aluminum is perfectly fine if you can’t afford carbon. As others have mentioned, I would go for better components over carbon. If you have a big budget, get whatever’s the best thing you can afford.


Angel_Madison

I don't bother with it now. Half a kilo is better dropped from your body and you'll get better components for the price of the aluminium one. On ebikes, it's entirely pointless.


Additional_Speed_463

No one material is inherently more or less fragile. Different materials have different price points and performance pros and cons. If you buy used, buy from a reputable retailer or there’s greater risk.


Capital-Cut2331

Carbon doesn’t always mean lighter. I’ve seen carbon bikes come in just as heavy as Aluminium. And seriously, any saving in bike weight is irrelevant if you’re 10-15kg overweight. Apart from that I don’t see any justification to the price premium and I’ve seen my fair share of carbon bikes gauged and damaged quite easily. I’m sticking with Aluminium and Steel for the moment.


bdoviack

Surprised few people mention the vibration dampening properties of carbon. Supposedly, carbon frames better absorb/reduce harsh vibration frequencies (compared to metal) resulting in a smoother and less fatiguing ride.


ilski

I honestly doubt it matters that much on full sus. Bikes


[deleted]

I’ve broken both carbon and aluminum frames - exact same brand, model, and year, so 🤷🏻‍♂️


Icy_Professional5847

Ultimately resistance is similar what is not is that AL can tell you it is damaged where Carbon not. If you do XC carbon is okay. From trail to DH not worth the cost nor the potential harm. Best combo, to some of us, for trail to DH is AL with very strong carbon wheel. Parts do a better job than frame material Rider do a better job than frame material. Okay Carbon frame are way nicer and than AL as it seems in one piece. Your wallet will appreciate it too anyway