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  1. #1
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    Steel vs. Aluminum bicycle frames - ride quality, etc.

    For those of you who are interested, here is some information regarding the difference between bicycle frames made of steel vs aluminum, that shound be, but isn't, common knowledge:

    Over eighty six percent of the energy loss on any bicycle is from the flexing of the frame ("the overall loss of the pedaler's energy due to friction in the bearings is found to be less than 1 percent. Chain losses would add 1.5-5 percent". Source: 'Bicycling Science' 2nd ed.). This energy loss depends on the properties on the material used.

    In the case of metals, it depends on the properties of them AFTER WELDING. No matter how good or how high tech the metal is, if it isn't welded good, it won't ride good. Two bikes made from the same tubing with the same design will steer the same, but one could be bumpy and hard to pedal and the other one could absorb bumps and be easy to pedal.
    The difference is in the weld quality and resultant change in the properties of the metal.

    We are mostly talking about steel here; all of our bikes are steel. Here's why:

    Some steel bikes ride better that titainium ones, and vice versa; however the special facilities required for the cutting and welding of titainium ($$$$), its price ($$), and its availability (USAF) mean that we cannot use it and meet our goal of a killer handwelded steel bike ($) for the price of an aluminum production bike($).
    Steel is a springy metal and aluminum is not (well, how many aluminum springs have you seen?). Aluminum bikes transmit high frequency vibrations (as do, to a lessor extent, poorly welded steel ones) while steel bikes absorb vibrations. The introduction of TIG (Tungsten Inert Gas) welding allowed a reduction of production costs for bikes, however the major impact was that use of an inert gas for welding allowed aluminum to be used for bike frames, despite its obvious deficiencies: transmission of vibration and a failure mode known as 'sudden and catastrophic.'

    Economics rules the world. Bike tubing is cheap. Welders are expensive. Aluminum is weak, so a thicker tube must be used. A thicker tube allows the use of a less skilled welder (which is harder to make, a pancake or a crepe?), and this is where the very major cost savings occur.

    Also, since thicker tubes are used in aluminum bikes, especially mountain bikes, the weight savings are not as much as one might think. This situation was put into very clear focus a few years ago when one of the bike companies we dealt with offered steel and aluminum mountain bikes at the same price. Our staff, and all customers who made a comparison, found that the steel bikes were a little easier to pedal and less bumpy, even if the steel bikes had no shock (this is because a shock is a low frequency filter but a high frequency pass,ie it does not do away with the undesirable properties of aluminum, just the gross features of the road surface-the 'jittery', high frequency bumps pass thtough the fork and frame to your hands).

    ...read the full guide with pics here

  2. #2
    Senior Member Nessism's Avatar
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    Quote Originally Posted by jimmayor007 View Post
    For those of you who are interested, here is some information regarding the difference between bicycle frames made of steel vs aluminum, that shound be, but isn't, common knowledge:

    Over eighty six percent of the energy loss on any bicycle is from the flexing of the frame ("the overall loss of the pedaler's energy due to friction in the bearings is found to be less than 1 percent. Chain losses would add 1.5-5 percent". Source: 'Bicycling Science' 2nd ed.). This energy loss depends on the properties on the material used.

    In the case of metals, it depends on the properties of them AFTER WELDING. No matter how good or how high tech the metal is, if it isn't welded good, it won't ride good. Two bikes made from the same tubing with the same design will steer the same, but one could be bumpy and hard to pedal and the other one could absorb bumps and be easy to pedal.
    The difference is in the weld quality and resultant change in the properties of the metal.

    We are mostly talking about steel here; all of our bikes are steel. Here's why:

    Some steel bikes ride better that titainium ones, and vice versa; however the special facilities required for the cutting and welding of titainium ($$$$), its price ($$), and its availability (USAF) mean that we cannot use it and meet our goal of a killer handwelded steel bike ($) for the price of an aluminum production bike($).
    Steel is a springy metal and aluminum is not (well, how many aluminum springs have you seen?). Aluminum bikes transmit high frequency vibrations (as do, to a lessor extent, poorly welded steel ones) while steel bikes absorb vibrations. The introduction of TIG (Tungsten Inert Gas) welding allowed a reduction of production costs for bikes, however the major impact was that use of an inert gas for welding allowed aluminum to be used for bike frames, despite its obvious deficiencies: transmission of vibration and a failure mode known as 'sudden and catastrophic.'

    Economics rules the world. Bike tubing is cheap. Welders are expensive. Aluminum is weak, so a thicker tube must be used. A thicker tube allows the use of a less skilled welder (which is harder to make, a pancake or a crepe?), and this is where the very major cost savings occur.

    Also, since thicker tubes are used in aluminum bikes, especially mountain bikes, the weight savings are not as much as one might think. This situation was put into very clear focus a few years ago when one of the bike companies we dealt with offered steel and aluminum mountain bikes at the same price. Our staff, and all customers who made a comparison, found that the steel bikes were a little easier to pedal and less bumpy, even if the steel bikes had no shock (this is because a shock is a low frequency filter but a high frequency pass,ie it does not do away with the undesirable properties of aluminum, just the gross features of the road surface-the 'jittery', high frequency bumps pass thtough the fork and frame to your hands).

    ...read the full guide with pics here

    This article is seriously flawed. Didn't even bother to read it based on the quote you posted. Comments added.


    QUOTE from above...
    For those of you who are interested, here is some information regarding the difference between bicycle frames made of steel vs aluminum, that shound be, but isn't, common knowledge:

    Over eighty six percent of the energy loss on any bicycle is from the flexing of the frame ("the overall loss of the pedaler's energy due to friction in the bearings is found to be less than 1 percent. Chain losses would add 1.5-5 percent". Source: 'Bicycling Science' 2nd ed.). This energy loss depends on the properties on the material used.

    Edit: energy loss due to frame flex is negligible. Not worth wasting time worrying about it unless you are talking about a frame that is so flexible that it throws the chain by itself and such.

    In the case of metals, it depends on the properties of them AFTER WELDING. No matter how good or how high tech the metal is, if it isn't welded good, it won't ride good. Two bikes made from the same tubing with the same design will steer the same, but one could be bumpy and hard to pedal and the other one could absorb bumps and be easy to pedal.
    The difference is in the weld quality and resultant change in the properties of the metal.

    Edit: this is not true. Welding quality does not change the ride quality in the least, it just effects durability.

    We are mostly talking about steel here; all of our bikes are steel.

    Here's why:
    Some steel bikes ride better that titainium ones, and vice versa; however the special facilities required for the cutting and welding of titainium ($$$$), its price ($$), and its availability (USAF) mean that we cannot use it and meet our goal of a killer handwelded steel bike ($) for the price of an aluminum production bike($).

    Steel is a springy metal and aluminum is not (well, how many aluminum springs have you seen?). Aluminum bikes transmit high frequency vibrations (as do, to a lessor extent, poorly welded steel ones) while steel bikes absorb vibrations. The introduction of TIG (Tungsten Inert Gas) welding allowed a reduction of production costs for bikes, however the major impact was that use of an inert gas for welding allowed aluminum to be used for bike frames, despite its obvious deficiencies: transmission of vibration and a failure mode known as 'sudden and catastrophic.'

    Edit: Steel does NOT “absorb vibrations”, in fact, it doesn’t damp vibration very much at all which is why it makes good springs. Don’t confuse a material that can flex with one that damps vibrations – they are completely different properties. Regarding aluminum, it doesn’t damp vibration either but IS quite springy, three times as much as steel. The reason aluminum bicycle frames are not flexi is because the material is prone to cracking and to get a reasonable life out of the frame, the flexing needs to be minimized. To minimize flexing on an aluminum frame the tubes are made large diameter and thick, thus the reason the ride quality is typically poor.


    Economics rules the world. Bike tubing is cheap. Welders are expensive. Aluminum is weak, so a thicker tube must be used. A thicker tube allows the use of a less skilled welder (which is harder to make, a pancake or a crepe?), and this is where the very major cost savings occur.

    Edit: thick steel tubes are easier to weld than aluminum – MIG can be used. That’s why so many kids bikes are made from thick steel.

    Also, since thicker tubes are used in aluminum bikes, especially mountain bikes, the weight savings are not as much as one might think. This situation was put into very clear focus a few years ago when one of the bike companies we dealt with offered steel and aluminum mountain bikes at the same price. Our staff, and all customers who made a comparison, found that the steel bikes were a little easier to pedal and less bumpy, even if the steel bikes had no shock (this is because a shock is a low frequency filter but a high frequency pass,ie it does not do away with the undesirable properties of aluminum, just the gross features of the road surface-the 'jittery', high frequency bumps pass thtough the fork and frame to your hands).

    ...read the full guide with pics here
    Last edited by Nessism; 07-14-08 at 04:48 PM.
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  3. #3
    Keep your line! Aller!Aller!'s Avatar
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    You know, through the 6 years that i raced, i owned 3 or 4 steel frames(Rossin, Raleigh, Bianchi, ?) and 1 aluminum one(Vitus). I didn't touch carbon or titanium as it was to crazy expensive.

    My Rossin became kinda soft after just one season. The steel used wasn't a high grade. The Raleigh was very stiff, yet it was a tad small for me making it a tight frame for my size which explains it rigidity.

    The Vitus one started out real nice, very light and comfy, but midway in the season, i started hearing some clics and tics. It also started riding very "smushy" for lack of a better word. It became so flexible under torque during sprints or climbs that it started changing my gears on its own. Near the end, the threading of the back stay where the rear derailleur is held stripped and the derailleur wouldn't hold and so i had to ship it back to France for repairs. I ended up trading it to a friend. At 6'2, 172lbs(at that time) i was big but not monster track rider size.

    My last and still current bike is a cromoly Bianchi, early '90s. Strong, smooth and stiff, great for my 200lbs body. It climbs well, sprints well, corners well...sure it's a tad heavy, but i have reservations on all those feather weight bikes out there. I'm still old school i guess
    Last edited by Aller!Aller!; 07-25-08 at 10:48 PM.
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  4. #4
    Senior Member Nessism's Avatar
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    Quote Originally Posted by Aller!Aller! View Post
    My Rossin became kinda soft after just one season. The steel used wasn't a high grade.
    Sorry to bash but this is another urban legend; steel does not get soft with usage. Check for yourself on the internet; google "steel fatigue". The metal maintains is same elasticity forever.
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  5. #5
    Keep your line! Aller!Aller!'s Avatar
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    I have to disagree...for some reason, after a season, it felt soft. Even some of my then riding friends who tried it felt a weakness in it. The lugs were fine, no cracks anywhere, no bends...traditional geometry through and through.

    Just one of those odd unexplainable things i guess.
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  6. #6
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    Quote Originally Posted by Aller!Aller! View Post
    I have to disagree...for some reason, after a season, it felt soft. Even some of my then riding friends who tried it felt a weakness in it. The lugs were fine, no cracks anywhere, no bends...traditional geometry through and through.

    Just one of those odd unexplainable things i guess.
    bikes are like kids, if you hug them and mother them they grow up all soft!!! you gotta treat em rough harden
    em up, take it out in the mud and give it a hiding, dont keep it inside. House bikes are *****s!!

  7. #7
    Decrepit Member Scooper's Avatar
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    Quote Originally Posted by Aller!Aller! View Post
    Just one of those odd unexplainable things i guess.
    Maybe mass hysteria?

    Steel frames going "soft" is one of those old wives tales that just won't die. Young's modulus is the same for all steels, and it doesn't change with age or use.
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  8. #8
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    Frames don't get soft; if your bike feels "soft" when it's a year or two old (assuming you're not just imagining it, which you are), try a pair of high-quality wheels; you'll probably find that the frame has suddenly regained its original stiffness.

    When is this myth of the harsh-riding aluminum frame going to be allowed to die a natural death? I've converted all my steel bikes to commuter use and do all my major miles on aluminum road and track bikes (4 hours today, 7 hours yesterday, track bike both times). Steel frames ride the same as aluminum to me; the only difference I detect is in torsional flex, which accounts for the way the wheels on steel frames don't track as predictably on descents as the wheels on aluminum frames.

    "Mass hysteria"! Excellence.

  9. #9
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    Quote Originally Posted by Trakhak View Post
    Frames don't get soft; if your bike feels "soft" when it's a year or two old (assuming you're not just imagining it, which you are), try a pair of high-quality wheels; you'll probably find that the frame has suddenly regained its original stiffness.

    When is this myth of the harsh-riding aluminum frame going to be allowed to die a natural death? I've converted all my steel bikes to commuter use and do all my major miles on aluminum road and track bikes (4 hours today, 7 hours yesterday, track bike both times). Steel frames ride the same as aluminum to me; the only difference I detect is in torsional flex, which accounts for the way the wheels on steel frames don't track as predictably on descents as the wheels on aluminum frames.

    "Mass hysteria"! Excellence.
    I have a steel hammer and it hammered nails in good for 6 months then it went 'soft' now it just sponges on the head of the nail.

    Should I get a aluminum hammer cause it will be stiffer?

  10. #10
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    this may be the funniest thing i've read on this issue to date. thanks for the laugh

  11. #11
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    i love the tales about how aluminum rides. obviously alot depends on design (duh). ride an early cannondale from the '80s with the elliptical seatstays in the non-aero orientation and then ride a vitus or an alan. then tell me if aluminum makes the stiffest frames or the flexiest.

  12. #12
    Senior Member Nessism's Avatar
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    It's easy to design an aluminum frame that will ride well, but keeping it from cracking is another matter. Aluminum, unlike steel and Ti, does not have a fatigue limit thus it can crack when subject to flexing. For this reason, aluminum frames are almost always designed to minimize flexing thus to extend the frames life and reduce warranty cost for the manufacturer.

    And those early Vitus and Alan frames did have a tendency to fail, mostly in the glue joints though.
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  13. #13
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    Quote Originally Posted by Nessism View Post
    It's easy to design an aluminum frame that will ride well, but keeping it from cracking is another matter. Aluminum, unlike steel and Ti, does not have a fatigue limit thus it can crack when subject to flexing. For this reason, aluminum frames are almost always designed to minimize flexing thus to extend the frames life and reduce warranty cost for the manufacturer.

    And those early Vitus and Alan frames did have a tendency to fail, mostly in the glue joints though.
    Working in bike shops in the '80s and '90s, I saw a lot more cracked steel frames than cracked aluminum frames. It's true that there were many more steel frames than aluminum frames on the road, but the difference was still striking. All that says is that manufacturers were pretty good at using both types of material to make frames that were acceptably light while "keeping the death toll from becoming prohibitive," in the words of Jobst Brandt.

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