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Carbon or aluminium
NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.
I am tossing up carbon or aluminium. Purchase price being no issue but suitability for my riding conditions and ongoing maintenance or durability is.
I ride mostly red hill, terry hills, Manly Dam with trips away. I like what I read about Carbon but I don't want it to become a problem if it's damaged on rock ect.
What's your 2c
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No issues with anything really. Rocks will chip any frame and they can dent aluminium frames. You cannot dent a carbon frame. Carbon frames have a special layer to allow for chipping and these days most frames have a bit of impact-absorbing material stuck on the downtube too.
Both frame materials tend to weigh about the same. At the limit carbon is much stronger and stiffer, but you aren't likely to get to the limit.
Currently I am riding carbon - I like that it is quieter and it just feels nice.
The aircraft industry is supposed to be the gold standard for use of carbon and boron composites. If anyone can get it right, you'd hope it would be them.
The long term fix for the wing cracks that have been plaguing the A380 Airbus was noted over the weekend in a SMH article as being the wholesale use of ... metal.
"Airbus's head of engineering, Charles Champion, said a permanent manufacturing solution for the wings of the A380s rolling off its production lines would not be made until the end of next year.
The permanent fix for new planes will involve ''using metal everywhere'' in the wing, replacing carbon-composite elements of the structure. In the meantime, interim fixes for those A380s in service has included replacing rib feet inside the wings of the planes"
Read more: http://www.smh.com.au/travel/travel-news/superju...
For myself, I have carbon bars and seatposts. If they're damaged, they're easy to inspect and relatively inexpensive to replace. A whole frame, though... I think I prefer aluminium given the number of little slips and slides I tend to have, and the number of scars on frame and shins from large sharp rocks flicked up by the front tyre.
There's not much point in making your frame last forever as they become outdated in a few years anyway. Think of how many 26 inch, hardtail, rim-brake bikes are gathering dust these days. I'd go for the carbon frame which is tougher and lighter.
After buying my first carbon bike 18 months ago I could never go back to aluminium.
However, I would choose some brands aluminium frames over other brands carbon.
Quality is probably the issue rather than frame material used.
For me, the major issue is the failure mode. When carbon fails, it does so catastrophically.
While metals can also fail that way given enough force, you usually get some warning, and they tend to bend rather than snapping outright.
out of curiosity, how many people on here have either had a carbon frame "fail" in some way or had it happen to someone they know personally (not just something they heard)? if so, was it just a crack or a catastrophic failure?
apart from particular frames with issues (like the scott ones that seem to crack a lot), i don't think i've heard about anyone breaking a frame. i've certainly never heard of a catastrophic failure.
A friend flicked a stick into the front wheel of a road bike, shearing off the carbon forks level with the rim, catastrophic for bike and rider. Whatever the fork material the same incident would have sent the rider over the bars, although the trajectory may have been different if the forks didn't snap. Straight laced wheels may be just as much to blame for allowing the stick to penetrate more easily than a cross laced wheel.
The only problem I have with my carbon frame is it seems to creak a lot, despite tightening and greasing everything twice.
Red Hill will break most bikes.
If you get something that’s a reasonable climber (meaning on the lighter side of things) it probably doesn’t matter what you get (carbon or alu), I’d almost guarantee that it will eventually fail if you ride up and down the drop zone enough, I would think that carbon will probably last longer if you don’t smash it up against all the rocks..?? but I’ve not had one to break up there yet.
Personally I’d stick with ALU for Red Hill (its no lycra clad latte sipping XC play ground) and I recommend that you go with a brand that’s got a reputation for sticking by their customers, then pick a good LBS to get it from. Yeti?
To answer your question, yes.
It was cracking only (fortunately!) but there have been plenty of catastrophic CF failures documented, some of which are the so-called strength tests of carbon frames apparently designed to put consumers' minds at ease, and others which have resulted in injury for riders.
I think Pikey had a seatpost go on a ride, and others have handlebars break off where the lock-on grip ends, so yes I am accepting some risk myself.
I reckon i'd choose a manufacturer that stands by its products over the long term (2 year warranties - what the?), then from that list, choose one or 2 bike models that you would like, then choose carbon or alu.
Personally i'm a fan of alu in heavier bikes, but i'd have carbon on a racing bike if i wasnt such a tightarse. And the downtubes and BB definately need protection on carbon bikes.
I agree with Hawkeye on this debate.
All frame materials will break eventually however carbon usually does so catastrophically whereas metal usually bend or crack first. These are usually detectable before complete failure occurs.
I work at RPH and I have treated 3 road cyclists in my time there with catastrophic failures. These all resulted in very serious injuries to the riders.
2 were forks and one was the headtube/toptube/seattube junction. All were road bikes though.
At the Anaconda race in Alice springs 3 years ago there was a dude who broke his carbon front triangle in 2. He was fine though.
I've broken 2 alloy frames so far but none catastrophically.
I won't own a carbon bike, and thats getting hard now cause most good bike brands are making their flagship bikes in carbon.
If "Purchase price being no issue - - -" is correct, by a carbon frame - (and if purchase price is really no issue, buy me one too.
wait for it!!
"Life's too short to ride boring bikes"
Get a quality carbon frame / bike from an experienced manufacturer...and never look back.
5 years on Carbon frames, not a single problem.
IMO the problems stated above are mainly due to cheap no-name eBay crap or wrong application / accidents caused by rider error.
/'nuf said...
http://vimeo.com/32301541
http://youtu.be/Y_O9PLorYPA
a much more scientific version from Santa Cruz
http://youtu.be/xreZdUBqpJs
I've put my carbon hardtail through hell and it amazes me how strong it is
... and of course, we never do that, do we?
The failures I'm aware of were all "name" brands, not ebay cheapies. Note I said "brands", plural.
I must admit it surprises me a little that people take reassurance from those videos, particularly the Niner and SC ones. Yes, they are stronger and that is a good thing, but have you not thought about how they fail when their limits are exceeded? Always into separate pieces. I don't find that particularly confidence inspiring.
Anyway, it's your teeth you're risking, not mine, so by all means pays your money and makes your choices.
if you hit something with enough force to break a carbon frame then unless you're chuck norris you're probably not going to be sitting on the bike anymore so i wonder how much bend vs crack would really matter.
hawkeye can you tell us what happened in the failures you are aware of?
I ride some very rocky Ungroomed p trails. Hwalls is infamous for it baby heads(big loose rocks)
Number of steel bikes I have broken: 4
Number of aluminum bikes I have broken in the last 12 years: 6
Number of carbon bikes I have brokensince making the switch: 0 (touch wood and all that)
Been riding a carbon bike since late 2008 and had a set of carbon cranks and seat post outlive 3 Al frames before that.
Of the Al frames I have broken 1 developed at crack and gave warning. 1 cracked 70% through and bent but most failed Ina big way without warning.
At the of the day if you are riding with in the design limits of the bike you should be fine either way and if not stone chips are the least of your worries
It's simple...
"Carbon bike riders just get lucky more often..." (....on and off the trails...)
You just float above the trails.... and you see the world from a different level...
Don't listen to the doubters...they just wished they had one...
In the age of lawsuits, I find it interesting that almost all quality bike makers are making their best, toughest, pro-standard downhill bikes out of carbon. Bikes that are designed to do stupid things, and where catastrophic failure costs dearly.
One lawsuit could wipe out a boutique bike builder overnight. Heck, even a mainstream bike company could be wiped out having to recall carbon frames. The financial hit is one thing, but damaged reputation?
Its true carbon usually fails catastrophically, but its also true that the breaking point is much higher, and as said, at that high breaking point, are you even going to be on the bike?
Put it all in perspective... the santa cruz carbon failed at ~930kg.
Try bench that tonight at the gym. Hell, try 90kg.
As opposed to the alu which peaked at 665kg. I say peaked because from what i can see it structurally failed around 450kg.
In that test the carbon is ~ twice as strong.
In impact testing things get more interesting...
Apply ye olde f=ma equation (think back to high school
)
The carbon frame survived a 392Nm impact
The alu survived a 153Nm impact.
The carbon is over 2.5x as strong.
Bottom line:
If you have to ask "which should i buy?"
The answer is "it makes no difference, you won't break either"
If you do break bikes, you know who you are and you are already riding carbon.
"The stiffness of a material is measured by its modulus of elasticity. The modulus of carbon fibre is typically 20 msi (138 Gpa) and its ultimate tensile strength is typically 500 ksi (3.5 Gpa). Compare this with 2024-T3 Aluminium, which has a modulus of only 10 msi and ultimate tensile strength of 65 ksi, and 4130 Steel, which has a modulus of 30 msi and ultimate tensile strength of 125 ksi.
Carbon fibre reinforced composites have several highly desirable traits that can be exploited in the design of advanced materials and systems. The two most common uses for carbon fibre are in applications where high strength to weight and high stiffness to weight are desirable.
Although carbon fibre has many significant benefits over other materials, there are also tradeoffs one must weigh against. First, solid carbon fibre will not yield. Under load carbon fibre bends but will not remain permanently deformed. Instead, once the ultimate strength of the material is exceeded, carbon fibre will fail suddenly and catastrophically."
So a carbon fibre bike should be stiffer and stonger than an aluminum bike, however, if you do push it beyond it's limits then chances are it will result in a catastrophic failure.
The problem with carbon materials on aircraft is due to UV and heat breaking up the resin. Once the paint chips off and the carbon becomes exposed it's pretty much gameover.
Given that a MTB will never be exposed to UV or heat in the way an aircraft will it's probably not a great comparison.
Most of them were front triangles cracking at the top tube near the seat tube junction, or a couple of inches back from the head tobe on either top or down tube. Some chain stays near the dropouts. The most worrisome were roadie forks. You really wanna pull it out and look at the steer tube and junction with the fork on a regular basis.
Theres an intrresting frame material properties chart on Lennard Zinn's site (of Art of Mountain Bike Maintenance fame). Included are steel, Ti,aluminium, carbon, and magnesium (yes you can apparently get frames in Mg). One of the properties he rates materials for is longevity. Carbon comes last.
I wouldn't say I wish i had a CF bike... more that I'm resigned to the likelihood that with the way the market is going with this fad,i won't have any other affordable option if I want something nice.
bustedcarbon.com is worth a look if you have some idle time
Pity this rider rode his carbon Niner frame instead of hitting it with a hammer.
His face might have fared better.
http://forums.mtbr.com/29er-components/catastrop...
Heres some boutique carbon failure with a lawsuit in progress.
I wouldn't call carbon a fad.
You could buy carbon bikes before you could buy full suspension or hydraulic brakes.
My current mtb is carbon, as was my last one. The one I'm looking at buying... You guessed it.
Yeh, was thinking about that. "Mania" is probably more appropriate than fad.
Hawkeye
Don't give us forum hearsay but facts and figures and pictures of local MTB frames... Otherwise it didn't happen.
Most of the stuff on bustedcarbon are stupid roadies with 6 kg bikes and tubes as thin as soda cans.. Go burly like Specialized or Santa Cruz...their carbon tubes are made of sturdy 2-3 mm thick cross-layered carbon, 5+ mm at the junctions.
Even Cannondale has finally learned that it makes sense to have thick walled carbon tubes.... See the new burly Scalpel.
I personally ride carbon because of its dampening qualities... It gets rid of the trail chatter (small bumps) / absorbs vibration which is good for the busted L4 on my spine. I wish they would make that part in carbon, too.
I had a carbon MTB bike crack in two places. Near the BB and on the downtube. I found them early so no major failure. The frame was a Cannondale so no surprises there!
"Don't give us forum hearsay but facts and figures and pictures of local MTB frames... Otherwise it didn't happen"
Sorry, no. Some are people on this forum, whom you already know in a few instances, and it's not up to me invest the time and effort to go take pictures of their bikes to prove anything just to win an internet debate. It's not a criminal prosecution ... is it?
Personally, I'd find doing so a bit invasive and creepy.
If they want to pipe up and back me up, they will. If not, I think it would be inappropriate to"out" them if they'd rather not say. In any case, there is already enough evidence in plain sight elsewhere. What weighting you want to give it is up to you.
If that looks like dodging the issue, this is me shrugging my shoulders -> v^O^v
If you want to believe it didn't happen, yeah, that's a choice you can make too.
Interesting that frame materials debates always seems to bring out such strong emotions, eh?
Hahahaha.
Hans, have you tried titanium for ye olde spine?
Titanium has really linear springy flex.
Unlike carbon which, as you said, soaks up small vibrations (which is great for road bikes), but once that nice springy flex limit is reached, its rock hard. Probably not the best thing for your back.
Probably better and cheaper to go carbon with a good dual suspension.
It depends if you crash a lot imo. LOL, Lots of crashes at RH will result in lots of skin off both you and the bike. In this case, aluminium will be your friend.
Otherwise, go Carbon!
Carbon can be layed to give stiffness where it's needed, and allow it to flex where they want. Making a frame comfortable and efficient at the same time, the technology being developed for bikes these days is mind blowing. As for strength, impact strength is much of a muchness, Sydney sandstone is pretty harsh, but the carbon frames seem to get scratched and don't really take too much of a beating.
I own both, My XC race bike is carbon and my AM bike is ally. But, I will be upgrading my Am bike (Orbea Rallon) to a carbon version one day when they get released.