What are the main differences between steel, aluminium and Carbon Fibre bikes?

Discussion in 'Bicycle Mechanics and Repairs' started by Manonabike, 18 Aug 2012.

  1. Manonabike

    Manonabike Über Member

    I heard a few times that the difference between a new bike and the old steel bikes are huge? Is it the weight difference? Or is it the frame design? Or perhaps modern parts make the difference?

    What would be the main differences between steel, aluminium and Carbon Fibre frames equipped with identical wheels and group set? Other that weight ^_^ which would offer the most comfortable ride?
  2. Octet

    Octet Über Member

    As far as I am aware, the main difference is weight. Using Carbon Fibre you can have the same/similar/stronger frame whilst having it at a fraction of the weight.
    I also believe that you can mould carbon fibre easier because it can be layered? Although I might be wrong.
  3. Smokin Joe

    Smokin Joe Legendary Member

    The one with the best tyres and tubes.
    lb81 likes this.
  4. Eddy

    Eddy Guru

    I have had all 3 and the main difference is carbon bikes are prettier:biggrin:!
    asterix likes this.
  5. sidevalve

    sidevalve Über Member

    Don't you believe it. The weight of a good quality steel frame is not that much different from an alloy one [many of which are actually heavier] and even carbon won't exactly make one look like a battleship. The all up weight of my old Dawes is only just over 10kg and there were many better and lighter than that. The real difference for most ordinary riding is £££££.
  6. Rob3rt

    Rob3rt Man or Moose!

    With alu, they could make bikes that were stiffer where it matters, by using larger diameter tubing and forming them, for the same or less weight as steel.

    With carbon, they just took it a step further really, able to really build up the material around the parts that needs to be stiff eg. bottom bracket etc. Also able to create more complex frame shapes with smooth joins etc.

    Also the materials do have different properties so will feel different to ride.
  7. 02GF74

    02GF74 Über Member

    there is no one answer but going by the materails properties, namely denisty and strength,, for a bike to have the same strength then the steel frame will be heaviet, followed by aluminium with CF lightest.

    when Al frames first appeared, they had a reputation of being very stiff so uncomfortable to ride as they would not absorb road shock, somemthing that steel frrames did but not so know since they are designed differently.
  8. Chrisc

    Chrisc Über Member

    My carbon frame is comfier than my ally frame was. So much so that I sold it despite the plan being to keep it for winter.
    I haven't ridden a well made steel frame so can't comment but I bet that's comfy too. I'd love to have a steel one made to measure one day. Hmm. Checks wallet....
  9. Mr Haematocrit

    Mr Haematocrit msg me on kik for android

    Out of the saddle
    Carbon fibre is a cloth which comes in different twill patterns, and is set using different grade resins. The pretty 2x2 weave most commonly associated with carbon fibre is by large a cosmetic finish. As such without understanding the grade of carbon being used in construction and the resin being used you are making very vauge assumptions.
    The layup process used for carbon fibre can drastically alter its strength, stiffness, weight, and characteristics and this changes the price of the product. The fact is not all carbon bikes are created equal.
    Specialized for example use a different grade carbon and layup process for the lower end carbon bikes than they do for the high end S-works models, this results in bikes which have the same frame size and dimensions but feel very different when ridden.

    Some great frames and great materials are available, and some less so.
  10. rusty bearing

    rusty bearing Über Member

    I prefer a good modern steel frame, bluff old traditionalist that I am. It's simply that of all the bikes that come through the workshop I've never ridden anything in ally or carbon that's as comfortable as my trusty steel tourer.
    tyred likes this.
  11. Octet

    Octet Über Member

    The interesting one to look out for in the future commercial market is the mix of carbon nano-tubes.
    I think a couple of racing bikes (Tour De France, expensive road bikes) use them, but as the cost comes down it should be interesting to see.
  12. asterix

    asterix Comrade Member

    Limoges or York
    On the Raid Pyrenean wot I did, I was one of 2 riders in 18 with a steelie, the rest being Alu or Carbon, 5-10 yrs younger than mine. (From discussions I was also 10 to 20 kg heavier than most.) I don't think the bike I rode made any significant difference other than the fact that it appeared to be a lot easier to descend mountains in pelting rain when you have mudguards, judging by the number of the 'guardless who got off and walked (the saddlebag was useful, too). One of us packed, quite near the end, and he was on carbon.
  13. overlander

    overlander Active Member

    No contest unless you need light weight steel is so much more comfortable. Infact if we had stuck with steel you would not need suspension on the cheaper bikes.
    Blue Hills likes this.
  14. Drago

    Drago Flouncing Nobber

    AL is very ductile, so the frames need to be more substantial than the equivalent steel, which means that compared to a good quality steel frame of similar size they can often be heavier.

    AL also has a low ductile limit, which emans that at best after some years a heavily used frame can feel 'dead' and unresponsive as that limit is approached and the frame loses it's springiness. At worst it can mean failure through what is commonly terms as metal fatigue.

    Steel on the other hand is less ductile, ie, it doesn't bend as much, but has a much higher ductile limit. In simple terms this emans that a steel frame will feel springy and fresh idnefinitely, provided it doesnt endure forces beyond it's ductile limit that causes it to permanently bend.

    Of the two, I'd have a well crafted frame from a good quality steel over AL any day.

    Titanium - wicked. Lots of pluses, not many downsides beyond the cost of the raw material and the difficulty in working it. This makes it relatively pricy, but if you can afford it.

    Carbon - it's a bit simplistic to say it's "good", because this all hinges on the material and cosntruction methods used. It is possibgle to construct and extremely light, stiff and durable frame, and with care in the design it is quite easy to tune the stiffness of various frame parts to tailor the quality of the ride. As a general rule you get what you pay for - general durability, resistance to UV degradation and weakening, and the quality of any bonding etc are likely to improve with the money spent. I personally wouldn't want a carbon frime for under £500 for the frame alone, but things are improving as more firms get into this. It is actually quite a simply, if labour intensive, process to manufacture carbon frames, largely on a par with handling fibreglass, so there is no techncial reason why it will remain expensive over time.

    Downside of carbon is it's resistance to impact and damage. Again though, experienced manufacturers are getting a grip on this and weaking in alloy plates etc under the sujrface layer to add protection.

    So for me I'd choose a juicy steel frame, but if I had the cash I'd be quite chuffed to go Ti or Carbon fibre, if they are are of good quality.
  15. Beyond certain material, production and transportation costs, the actual selling price of a frame is largely irrelevant. Retail pricing is not (in this context) a good predictor of frame quality.
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