can carbon be trusted..

delcol
delcol Posts: 2,848
edited November 2010 in MTB general
i just sold the heckler a few weeks ago and i am in the process of choosing a new bike i have a few inmind, one of them being the new ibis hd which is carbon,, i can get it at a decent price due to a contact,, but my concern is can carbon be trusted has it proved itself yet,,,
i hear so many ppl say oh it crumples oh it splinters blah blah blah,,, i know gt and santa cruz ran carbon frames in the world cup this year ,,, i know mr lopes won the whistler aline down hill on a hd,,,
i just want to be sure before i lay down a few grand on my new beast..
has any of you guys gals any expierence with carbon frames,,. how do they hold up to the abuse of mtbing in mountainous terrain..
i have seen the video of the cannondale vs the hammer to and the vice,,,,
thanks.... dc
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Comments

  • njee20
    njee20 Posts: 9,613
    Nope, not tough enough at all, it can snap on anything more than a kerb, and even a kerb if you get it wrong.

    Just think, if it was strong enough for a mountain bike, then they'd build silly things like aircraft and formula one cars out of it, where strength doesn't really matter.

    Oh... wait.
  • joshtp
    joshtp Posts: 3,966
    mark webber's crash at the start of this F1 season.


    He's (not) dead now.
    I like bikes and stuff
  • chrisga
    chrisga Posts: 587
    Funny, I love all things carbon. Think its amazing stuff. Have had boats made out of it, it is seriously strong stuff. Plenty strong enough for a bike frame from an engineering POV as proved by the riders/manufacturers you mentioned above. I think you'd struggle to snap a frame through normal riding.

    However, having said that, I do have a carbon frame in the garage that is now unusable due to 2 minor mishaps. The first happened when the previous owner fell over and the driveside seatstay hit the corner of a rock and splintered. One thing that many people dont think about when slagging off carbon is that it can actually be repaired if you know what you are doing a lot easier than if you damaged a tube on your alumium or steel bike. I had my frame repaired by a friend who makes sailing dinghies from carbon and knows his onions. I had every confidence that it would be fine. And it was, right up until a wheel with no tyre on fell a couple of feet from a hook on the wall of the garage and splintered and cracked the top tube. I've given up with that frame now and bought an on-one summer season. From one extreme to the other.....

    Carbon isnt very good with puncture resistance. Which is kind of why trek have added rubber guards to the downtube of remedys I guess.

    Would I recommend a carbon frame? Absolutely. If you take care of it I bet it will give you years of hassle free biking and you wont break it, however my post is really just to make you aware that it does have limitations and certain semingly small accidents could have a serious impact and render it useless.
  • chrisga wrote:
    Would I recommend a carbon frame? Absolutely. If you take care of it I bet it will give you years of hassle free biking and you wont break it, however my post is really just to make you aware that it does have limitations and certain semingly small accidents could have a serious impact and render it useless.

    + Potato on that very valid point.
  • It definitely can't be trusted. Turn your back on it and it'll nick your wallet AND shag your wife.
  • njee20
    njee20 Posts: 9,613
    however my post is really just to make you aware that it does have limitations and certain semingly small accidents could have a serious impact and render it useless.

    What if a 1kg object fell 2 foot onto an aluminium frame of even a similar weight? I doubt it'd be fine!
  • psymon
    psymon Posts: 1,562
    i know what you mean.

    its an amazing material, i had some bontrager carbon bars for a while and loved em, but if it is one of the holy grails of frame materials why do Trek feel the need to add a downtube protector?

    Ive built carbon bikes where you can push the tube in with your thumb!
    its strong in the direction its supposed to be but less so in the ones its not.
  • dennisn
    dennisn Posts: 10,601
    Just don't let it get wet or it will melt. Other than that, great stuff.
  • Carbon is awesome at doing what it is aimed at. What i mean by this is that it allows manufacturer to build a bike that can be stiff for efficiency just by laying the fibres and different materials in certain directions. At the same time produces a comparitively light end result. There are so many different variations of carbon fibre resin system out there the manufacturer can build the perfect machine for each scenario i.e. make a real light road bike with great stifness for climbing but not less focused on impact resistance or make a stronger/heavier xc mtb with better shock and flex absorbtion properties than titantium or steel. There have been so many carbon frames produced over the years now which should have allowed a suitable knowledge gain the main companies will have really cracked the important design characteristics.
    However what carbon fibre is not good at is impacts which trigger voids and micro fractures. I am not saying it will break on first, second, twentieth heavy fall but impacts on sharp rocks are not good for the frame and risk setting of weakenesses which may not be visible on the outside. Sorry but I don't agree you can repair damaged carbon fibre properly. Yeah you could cover it up and bond the sections back together but the strength comes from the original cure process and once broken through the original carbon layers the part will be a lot weaker and needs to be replaced. Time is another factor. People need to realise carbon fibre does not last for life, the performance degrades over time. F1 cars, plane parts made from carbon are all lifed so that at a certain number of hours they are replaced because the manufacturers know that the part will be weaker than when first made and the risk of failure rises significantly. So don't expect your carbon bike to last you 30 years like a titanium one might.
    Would I buy a carbon frame. Yes I own 2 road bikes and 1 xc bike in carbon. Like most people I try to minimise the number of times I fall of my bike but they have all taken a few bangs and luckily all still fine from what I can see. I wouldn't buy a heavily worn 2nd hand carbon frame as you don't know what has happened to it or how bad an impact it might have taken. I also wouldn't buy a carbon DH bike as thats a sport inherent with hitting things. Fine for the pros who can replace bikes regularly but unless you got deep pockets and don't mind replacing probably not worth doing.
    Final rant. Lot of people try and blame the manufacturer when a carbon frame fails 2 years down the line. Let me tell you now, if there was a manufacturing fault with the frame then it would fail very soon after initial use and not 2 years down line. If it fails 2 years later it was probably something you hit or did which triggered the build upto the breakage so man up and make sure you have suitable insurance cover in place rather than trying to blame the manufacturer.
    Good luck.
  • Where is that video of the carbon frame v a hammer and the alu alternative?
  • delcol
    delcol Posts: 2,848
    sweet some good replies coming in here,, keep em coming,,,

    this is what i'm looking for good decent real life advice,,,,

    i would hate to shell out the 2k frame price and kill it first trip to whistler,, i'm not opening a can of worms here just stating.,, had the heckler 3 years it did six trips to whistler and took many a stack some minor some quite major,, the frame was still good working order when i sold it,,,
    whats the difference in the way a carbon bike frame is made to the way a f1 car or road car (think zonda and ferrari) or aircraft parts are made,... is there a difference...

    i just want to be 100% sure before i make my purchase,,,,,

    oh and it is more than welcome to steel the wife and there's never much in the wallet anyway....
  • supersonic
    supersonic Posts: 82,708
    take a 3lb steel frame, or alloy frame and drop it on a rock and quite often it will leave a big dent. Oh wait, we dont have 3lb steel frames...
  • ride_whenever
    ride_whenever Posts: 13,279
    you can get 1.1kg steel road frames (953 steel FTW)
  • njee20
    njee20 Posts: 9,613
    Alright, drop them on a pointy rock even once, see how it comes out! Now repeat with an 1100g carbon frame, I'll bet it'll be in a better state!
  • ddraver
    ddraver Posts: 26,558
    psymon wrote:
    ....why do Trek feel the need to add a downtube protector?

    D'you know i reckon that may well be a marketing ploy. My main worry with buying a carbon bike would be downtube strikes from flying rocks and it would give me peice of mind (if i could afford any of them)
    We're in danger of confusing passion with incompetence
    - @ddraver
  • SDK2007
    SDK2007 Posts: 782
    I've had my carbon All Mountain bike nearly 3 years, approx 2,000 miles riding and it's taken everything in its stride, including

    - All Wesh trail centers
    - All Scotland 7Stanes centers - all black runs
    - Fort William - Nevis Red Run x 5
    - Fort William - Orange DH course

    Along the way I’ve had plenty of crashes; some small and some big ones at 20mph+ on rocks and the carbon frame hasn’t missed a beat.
  • Heard a rumour Steve Peat is scared to ride his new carbon V10 in the rain in case it melts !!!!

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  • Stevo_666
    Stevo_666 Posts: 59,811
    Heard a rumour Steve Peat is scared to ride his new carbon V10 in the rain in case it melts !!!!
    Well exactly. I'm no carbon fibre guru but if the like of Santa Cruz are happy to make DH bikes and big hit trail/enduro bikes like the Nomad in Carbon then I don't see what the worry is about. CF technology seems to be past the experimental stage.
    "I spent most of my money on birds, booze and fast cars: the rest of it I just squandered." [George Best]
  • supersonic
    supersonic Posts: 82,708
    In a few years time all race bikes accross the spectrum will be carbon fibre. We will see more sub 1k bikes with them. It has come of age.
  • joshtp
    joshtp Posts: 3,966
    supersonic wrote:
    In a few years time all race bikes accross the spectrum will be carbon fibre. We will see more sub 1k bikes with them. It has come of age.

    I'm not so sure... but I do think Carbon is great, I'm all for it. My mate has a carbon Ransom. It's as light as my 140mm Ht (although that's partly due to the posh build) And he's raced the mega a few times, and all sorts of other stuff, including his fare share of DH tracks on it for the past few years and its fine.
    I like bikes and stuff
  • psymon
    psymon Posts: 1,562
    maybe some kind of crash replacement programme, like with helmets, is the answer?
  • Anonymous
    Anonymous Posts: 79,667
    njee20 wrote:
    Nope, not tough enough at all, it can snap on anything more than a kerb, and even a kerb if you get it wrong.

    Just think, if it was strong enough for a mountain bike, then they'd build silly things like aircraft and formula one cars out of it, where strength doesn't really matter.

    Oh... wait.
    :lol:
  • ashleymp777
    ashleymp777 Posts: 1,212
    Well i've justy taken delivery of my 2nd carbon bike, a Yeti AR5 and I cant wait to ride it. Had a carbon hardtail for a couple of years and it is nothing short of brilliant, no prblems whatsoever!
  • Northwind
    Northwind Posts: 14,675
    As long as it's been made right, it's fine. But not all carbon fibre stuff is made right. And the bad stuff over the years has helped give the good stuff a bad name.

    One thing that people consistently misunderstand... They think that there's a chip in their carbon component, so it's ruined. Absolute rubbish, the top coat is nonstructural, or at least it is in every carbon part i've ever seen- perhaps some short lifespan race kit is different. If you chip it, it's much the same as chipping the paint on a metal frame, it just doesn't matter at all. That can go further, many parts have a nonstructural top weave (largely for cosmetic reasons), which means that even if you manage to get into the fibres, the part still isn't affected at all. Course, any damage that manages to get into the top layer of the weave may have penetrated further.
    Uncompromising extremist
  • psymon
    psymon Posts: 1,562
    why do carbon bars need anti crush (metal insert) sections?

    plus all but the most expensive carbon frames still require some alloy sections, droputs etc.

    i want to trust it, but part of me doesnt, to the point that if i win the lottery tonight i will be buying an ally Nomad.
  • Northwind
    Northwind Posts: 14,675
    psymon wrote:
    why do carbon bars need anti crush (metal insert) sections?

    plus all but the most expensive carbon frames still require some alloy sections, droputs etc.

    To your first-they don't, but many do, just because carbon fibre tubes need a fair amount of material to be crush resistant, so an aluminium insert can be more effective than layering up the carbon fibre (it's also partly idiot-proofing- most people overtighten their stems and brakes, it's quite a natural thing to do since the correct torques feel so low. So a smart designer plans for that, one way or another)

    For the second- sure they do, some parts make more sense to make with aluminium. Is that an issue? If you buy a steel cotic it'll have an aluminium mech hanger, does that prove some failing of steel? Likewise if you buy an alu frame it'll have steel bolts. Different materials for different jobs.
    Uncompromising extremist
  • bike-a-swan
    bike-a-swan Posts: 1,235
    Some carbon frames use ally bits in brake fixings and the like because of the thermal requirements. You can get carbon that'll cope with heat, so I'm guessing it's either a cost or technical difficulty thing preventing everyone from doing it...
    Rock Lobster 853, Trek 1200 and a very old, tired and loved Apollo Javelin.
  • delcol
    delcol Posts: 2,848
    thanks for all your imput,, keep the advice coming,,,

    i guess carbon has proved its self and is a trustworthy option then,,, ummmmmmmmmmmmmm could my new steed be a mojo hd.....