Difference in Aluminum types

Discussion in 'Mountain Bikes' started by Jennifer Smith, Feb 1, 2003.

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  1. I got a question on the difference between Aluminum alloy types.

    What are the characteristics of Al 7075 and other types of Al?

    i.e. I currently have a handlebar made from Al 7075 & it flexes quite a bit. I have nightmares of
    coming down a rocky section of trail and having my Al 7075 bars breaking from the metal
    fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid because my
    understanding of Al is that it doesn't flex to much & is prone to failure.

    Does any know of a good website explaining the different types of Al & their properties?

    Thanks.'
     
    Tags:


  2. Slacker

    Slacker Guest

    "Jennifer Smith" <[email protected]> wrote in message
    news:6i%[email protected]...
    > I got a question on the difference between Aluminum alloy types.
    >
    > What are the characteristics of Al 7075 and other types of Al?
    >
    > i.e. I currently have a handlebar made from Al 7075 & it flexes quite a bit. I have nightmares of
    > coming down a rocky section of trail and having my Al 7075 bars breaking from the metal
    > fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid because
    > my understanding of Al is that it doesn't flex to much & is prone to failure.
    >
    > Does any know of a good website explaining the different types of Al & their properties?
    >
    > Thanks.'

    IMHO that's not going to give you the necessary info you're looking for. Two companies could use the
    same material, but one might make a flexy POS with the other making a super stiff one. Plus some
    companies are using are using proprietary material for their bars. Don't you just want to know who
    makes a good bar??

    My riding weight is bout 200 lbs and I'm using an
    http://cambriabike.com/bars&ends/answer_protaper_aluminum_riser_bar.htm for both XC & DH. It's a
    great bar....strong & stiff. There are others too.

    --
    Slacker
     
  3. Jose Rizal

    Jose Rizal Guest

    Jennifer Smith:

    > I got a question on the difference between Aluminum alloy types.
    >
    > What are the characteristics of Al 7075 and other types of Al?

    http://www.metalsonline.com/Research/Property/step1.asp

    > i.e. I currently have a handlebar made from Al 7075 & it flexes quite a bit. I have nightmares of
    > coming down a rocky section of trail and having my Al 7075 bars breaking from the metal
    > fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid because
    > my understanding of Al is that it doesn't flex to much & is prone to failure.

    Essentially, flexing aluminium alloy structures is not ideal since Al's fatigue life is much shorter
    than steels and flexing tends to imply a high load. Also loads on Al alloy structures are cumulative
    in terms of fatigue life, whereas loads on steel structures have negligible effect on fatigue life
    when below a critical value, even when flex is present. Consider that most springs are made of
    steel, whereas Al springs are unheard of.

    If your handlebar's flexing is making you nervous, get one meant for downhill riding: these tend to
    be thicker (and heavier) and might flex a lot less.

    > Does any know of a good website explaining the different types of Al & their properties?

    See above.
     
  4. Mark Hickey

    Mark Hickey Guest

    "Jennifer Smith" <[email protected]> wrote:

    >I got a question on the difference between Aluminum alloy types.
    >
    >What are the characteristics of Al 7075 and other types of Al?
    >
    >i.e. I currently have a handlebar made from Al 7075 & it flexes quite a bit. I have nightmares of
    > coming down a rocky section of trail and having my Al 7075 bars breaking from the metal
    > fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid because
    > my understanding of Al is that it doesn't flex to much & is prone to failure.

    In essence, you won't find any aluminum bars built with the same wall thickness that act much
    difference. To grossly oversimplify, all the aluminum alloys used in the bike business acts
    about the same.

    There is a tradeoff between increasing the ultimate shear strength and the ductility (the ability of
    the material to stretch without being permanently deformed, more or less). The two goals are
    normally at odds with each other - think of it in terms of a fine china plate on one end of the
    scale and a frisbee on the other... but with all the "normal alloys" being clumped near the center
    of the range.

    >Does any know of a good website explaining the different types of Al & their properties?

    There are a lot of them out there, but I doubt you'll find one that really digs deep enough to
    answer the specific question you're asking. In the end, design, material purity, and quality control
    are the things that will keep you out of trouble. The easy answer is to replace your bars every year
    with relatively heavy aluminum bars (kind of a brute force insurance policy). Stay away from
    ultra-light (aka stupid-lite) bars if you have a flex issue with your current bars.

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  5. John Morgan

    John Morgan Guest

    > i.e. I currently have a handlebar made from Al 7075 & it flexes quite a
    bit.
    > I have nightmares of coming down a rocky section of trail and having my Al 7075 bars breaking from
    > the metal fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid
    > because my understanding of
    Al
    > is that it doesn't flex to much & is prone to failure.

    Daaaaamn! That's one big woman!

    -John Morgan
     
  6. Mark says:

    >the ductility (the ability of the material to stretch without being permanently deformed, more
    >or less).

    I'm going to bet that the Resident Metallurgist (UK branch) is willing to correct me if I'm wrong,
    but that quality is called elasticity, not ductility, IIRC

    Steve just don't ask me what "ductility" _is_ though....
     
  7. Simon

    Simon Guest

    "Stephen Baker" <[email protected]> wrote in message
    news:[email protected]...
    | Mark says:
    |
    | >the ductility (the ability of the material to stretch without being permanently deformed, more
    | >or less).
    |
    | I'm going to bet that the Resident Metallurgist (UK branch) is willing to correct me if I'm wrong,
    | but that quality is called elasticity, not
    ductility,
    | IIRC
    |
    | Steve just don't ask me what "ductility" _is_ though....

    Elastic deformation: nonpermanent deformation, totally recovered upon release of an applied stress.

    Ductility: A measure of a material's ability to undergo appreciable plastic deformation before
    fracture; it may be expressed as percent elongation or percent area reduction from a tensile test.

    In essence you are both correct but within varying parts of the original post. I believe the elastic
    deformation is what is happening within the bars and the ductility that Mark H was referring to was
    within the process of actually making them.

    Simon.....Paid semi attention at university :eek:)
     
  8. Zerohm

    Zerohm Guest

    "Simon" <[email protected]> wrote in message
    news:2Kl%[email protected]...
    >
    > "Stephen Baker" <[email protected]> wrote in message
    > news:[email protected]...
    > | Mark says:
    > |
    > | >the ductility (the ability of the material to stretch without being permanently deformed, more
    > | >or less).
    > |
    > | I'm going to bet that the Resident Metallurgist (UK branch) is willing
    to
    > | correct me if I'm wrong, but that quality is called elasticity, not
    > ductility,
    > | IIRC
    <snip>

    Have a look at www.principalmetals.com which gives a very good explantion of the differing grades of
    aluminium and has an excellent glossary of terms...

    Zerohm
     
  9. Jose Rizal

    Jose Rizal Guest

    Stephen Baker:

    > Mark says:
    >
    > >the ductility (the ability of the material to stretch without being permanently deformed, more
    > >or less).
    >
    > I'm going to bet that the Resident Metallurgist (UK branch) is willing to correct me if I'm wrong,
    > but that quality is called elasticity, not ductility, IIRC

    Correct. Ductility is the ability to deform permanently. Amongst gold's valuable properties is its
    high ductility, easily deformed into any shape.
     
  10. Andy Chequer

    Andy Chequer Guest

    "Simon" <[email protected]> wrote in message
    news:2Kl%[email protected]...
    >
    > "Stephen Baker" <[email protected]> wrote in message
    > news:[email protected]...
    > | Mark says:
    > |
    > | >the ductility (the ability of the material to stretch without being permanently deformed, more
    > | >or less).
    > |
    > | I'm going to bet that the Resident Metallurgist (UK branch) is willing
    to
    > | correct me if I'm wrong, but that quality is called elasticity, not
    > ductility,
    > | IIRC
    > |
    > | Steve just don't ask me what "ductility" _is_ though....
    >
    > Elastic deformation: nonpermanent deformation, totally recovered upon release of an
    > applied stress.
    >
    > Ductility: A measure of a material's ability to undergo appreciable
    plastic
    > deformation before fracture; it may be expressed as percent elongation or percent area reduction
    > from a tensile test.
    >
    > In essence you are both correct but within varying parts of the original post. I believe the
    > elastic deformation is what is happening within the
    bars
    > and the ductility that Mark H was referring to was within the process of actually making them.
    >
    > Simon.....Paid semi attention at university :eek:)

    Just how many metallurgists are there around here?

    Andy Chequer
     
  11. Shaun Rimmer

    Shaun Rimmer Guest

    Andy Chequer <[email protected](removethisbittosend)secretworldgovernment.org> wrote in message
    news:YzR%[email protected]...
    >
    > "Simon" <[email protected]> wrote in message
    > news:2Kl%[email protected]...
    > >
    > > "Stephen Baker" <[email protected]> wrote in message
    > > news:[email protected]...
    > > | Mark says:
    > > |
    > > | >the ductility (the ability of the material to stretch without being permanently deformed,
    > > | >more or less).
    > > |
    > > | I'm going to bet that the Resident Metallurgist (UK branch) is willing
    > to
    > > | correct me if I'm wrong, but that quality is called elasticity, not
    > > ductility,
    > > | IIRC
    > > |
    > > | Steve just don't ask me what "ductility" _is_ though....
    > >
    > > Elastic deformation: nonpermanent deformation, totally recovered upon release of an applied
    > > stress.
    > >
    > > Ductility: A measure of a material's ability to undergo appreciable
    > plastic
    > > deformation before fracture; it may be expressed as percent elongation
    or
    > > percent area reduction from a tensile test.
    > >
    > > In essence you are both correct but within varying parts of the original post. I believe the
    > > elastic deformation is what is happening within the
    > bars
    > > and the ductility that Mark H was referring to was within the process of actually making them.
    > >
    > > Simon.....Paid semi attention at university :eek:)
    >
    > Just how many metallurgists are there around here?

    Not enough.

    Shaun aRe - There is no such thing as 'too many metalurgists'. It's a fact.
     
  12. Supabonbon

    Supabonbon Guest

    "Slacker" <[email protected]> wrote in message
    news:<Yh0%[email protected]>...
    > "Jennifer Smith" <[email protected]> wrote in message
    > news:6i%[email protected]...

    > > What are the characteristics of Al 7075 and other types of Al?
    > >
    > > i.e. I currently have a handlebar made from Al 7075 & it flexes quite a bit. I have nightmares
    > > of coming down a rocky section of trail and having my Al 7075 bars breaking from the metal
    > > fatigue. Are there better alloys of Al that won't flex so much or am I just paranoid
    > > because my understanding of Al is that it doesn't flex to much & is prone to failure.
    > >
    > > Does any know of a good website explaining the different types of Al & their properties?
    > >
    > > Thanks.'

    >
    > My riding weight is bout 200 lbs and I'm using an
    > http://cambriabike.com/bars&ends/answer_protaper_aluminum_riser_bar.htm for both XC & DH. It's a
    > great bar....strong & stiff. There are others too.

    Or you could go steel: http://www.profileracing.com/ /s
     
  13. Shaun Rimmer

    Shaun Rimmer Guest

    Andy Chequer <[email protected](removethisbittosend)secretworldgovernment.org> wrote in message
    news:eek:KY%[email protected]...
    >
    > "Stephen Baker" <[email protected]> wrote in message
    > news:[email protected]...
    > > >Just how many metallurgists are there around here?
    > > >
    > > >Andy Chequer
    > > >
    > >
    > > <grasshopper> Only you, master! </grasshopper>
    > >
    > > ;-)
    > >
    >
    > I'm not sure wether that was wierder than aRe's post. I suspect that you
    are
    > both very strange.

    He makes an awkward but willing and ca[able apprentice - He actually brought me a bucket of steam,
    but spilt half of it on the way.

    Shaun aRe
     
  14. > Just how many metallurgists are there around here?
    >
    > Andy Chequer
    >
    >

    Umm, there's me, though I'm more of a chemical metallurgist (blast furnaces/smelting/phase diagrams)
    kinda guy. Keep my mouth almost shut on the physical metallurgy side of life. I am sort of a chronic
    lurker though.

    There's another metallurgist from Los Alamos in the rec.bicycling.* world. Dave K is a very
    knowlegable guy.

    Anyway -- it's all about design and manufacturing finnese, not materials in these low stress,
    undemanding operational environment machines we call bicycles.

    Mike Johnson Los Alamos, NM
     
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