snailracer
Über Member
Here's a link to an amusingly archaic article about CF from way back in 1968, entitled "The New Steel" :
http://www.flightglo...20-%202417.html
http://www.flightglo...20-%202417.html
lmao....i really am....<bang bang bang> <<<that's my head thumping repeatedly against the keyboard.
Steel is being superseded in planes, but the state-of-the-art 787 Dreamliner still has about 10 tons of steel, compared to 35 tons of CF.
The fuselages of many modern light aircraft are still made of steel frames supporting aluminium panels - steel is still cost-effective if you need to weld parts together.
Some cold-war Soviet warplanes were made almost entirely of steel so they could be mass-produced (and could still fly at mach 3) and are still flying.
CF doesn't suffer from fatigue failures as far as is known. Other, long-term failure modes may exist, nobody really knows for sure.
My point wasn't that CF is somehow intrinsically crap, it's that engineers aren't that good at designing/manufacturing with it, and the service & maintenance aspect barely exists for bicycles - how many bike shops have ultrasonic scanners and endoscopes?
Boeing (787 stringers), Airbus (rudder, tail) and Trek (fork steerers) have all had high-profile failures of CF components. CF failure isn't even new - Rolls-Royce tried and failed with CF compressor blades in their jet engines in the 1960's, which was so disasterous the company went broke.
Those companies are the best manufacturers in their respective fields - if they can screw up their CF designs, that suggests to me that CF still isn't quite ready for the mainstream.
In addition to the CF, the Dreamliner contains about 30 tons of fibreglass (CF's less-pretty composite sister) - a proven, tough material that fails in a non-catastrophic manner.
My point was that steel is still used in modern planes, even the brand-new Dreamliner has 10 tons of it.You'll find that all that steel is in the engines, which have to withstand very high temperatures - something that Al can't do. Ti can, but it's expensive, and the nickel superalloys you find in the turbine stages do better, as they have outstanding creep resistance (they don't deform under load when hot)...
You sure about that? Fibreglass is really tough, it's not brittle like glass....You do realise the "glass" bit in fibreglass is in fact, err, glass? And glass reinforced plastic most certainly fails in a brittle fashion. It certainly is not "tough" in the fashion that engineering metals are...
Since the 1960's. But they'd rather you overlook the first 25 years....Carbon fibre has been used in aviation for over twenty years now...
But that's my point, the manufacturers still get CF design wrong with amazing frequency. Maybe their design tools and methodologies still aren't good enough when it comes to CF....There is one crash that I can think of involving the failure of a carbon part - the failure of the tail section of an Airbus in the November 2001 New York crash. That was a result of inappropriate pilot repsonse to wake turbulence which overloaded the rudder. It broke when subjected to 2.7 times its maximum design load. Aviation experience demonstrates quite clearly that carbon fibre is perfectly safe with the correct design and fabrication...
CF steerers crack, Al steerers fatigue and then snap, or just come unglued. Get a steel one ....The failure in the OP was at the point where the steerer tube is subjected to the maximum bending forces from the load applied to the handlebars. It was probably fatigue failure. Ironically the steerer would most likely not have failed had it been carbon fibre, as CF is much more resilent against fatigue than aluminium...
funnily enough i was down at my lbs today where i got my giant tcx1 from. i was enquiring about the possibility of getting a set of alloy forks. i just don't seem to be able to settle down when riding with the carbon forks it came with, my reasons to be unsettled is that my scott genius ltd full carbon fibre mtb (£5000's worth) snapped in half due to a manufacturing fault (fracturing my eye socket and wrist and i was knocked unconscious for a short while). the frame was replaced by scott and the bike rebuilt by lbs, but i ebayed it.
the bloke at the lbs (craig at rideon in rossendale) is very knowledgeable and is involved in quite a few research and developments (bike related). rideon are giant dealers and craig goes to all the meetings a dealer has the opportunity to goto. he's been to a few where giant rep's talk about quality and prices and some others where they demonstrate the manufacturing process and quality control.
apparently not all cf is the same, i.e giant get the actual fibre's from the same place as boeing and f1 teams. in other words they get the best available, then they weave it in house and produce the components in house and keep a tight grip on quality. apparently giant have the ethos of it has to be 'fit for purpose' (which causes passionate arguments at dealer meetings, dealers want cheaper bikes to compete) and not built to compete with 'boutique' brands on lightness (eg, pinarello, colnago etc etc) the boutique companies buy in the already woven cf matting and 'swatch build' their frames with the ultimate goal being lightness and stiffness (fair enough, horses for courses).
giant actually build and have their bikes tested to some crash test standards (craig said EN summat or other) and are heavily involved with improving the standards of all bicycle frames and forks. craig says he really believes the company (giant) operate a show all policy and gets monthly emails regarding failures and recalls. he reckons in all the time he's been a dealer he's not heard (not even on the grapevine) about any problems with giant cf frames or forks.
now i'm not naive enough to believe everything i'm told by a dealer (obviously he may have an agenda) but craig seems to be a straight up guy and wouldn't sell cf mtb bikes until he started being a giant dealership.
what do you guys think? has he been straight with me (or giant straight with him).
i'm particularly happy with how he told me giant make their cf forks; a swaged end on an alloy steerer tube and then inserted into the machine that bonds the tube to cf & resin, i.e., not cold glued into a crown like a lot of companies used/do.
ribble bikes was one of the companies that was mentioned in the cheap chinese carbon category.
Wood is the only material that gives you plenty of warning before collapsing. Bamboo? Not too sure yet.
Unlike bikes the air frames of aircraft have a very well planned out service life in actual hours.Next we know the OP will be warning against flying - all those dangerous weak Al and carbon fibre planes ought to be replaced with steel ones
Who are these mind-bogglingly ignorant people who go on about the 'strength' of a material as if it only comes in one - dangerous - form? I suggest they all move to wood bikes and avoid all technological materials as occasionally some component makes it past the QA test and fails in use. Humans being fallible, it's always going to happen
I'm tempted to start a thread about carbon fibre helmets with built-in headphones .these material threads are becoming like helmet threads