Opinions on aluminum frames?

Discussion in 'Road Cycling' started by Archer, Mar 13, 2003.

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  1. Peter Cole

    Peter Cole Guest

    "Mike S." <[email protected]> wrote in message news:[email protected]...
    >
    > How can you sit there and tell me that the shape/diameter of a tube doesn't affect its ride? If a
    > 1" tube is x stiff, a 2" tube is 8x stiffer, that won't affect ride quality? If the material used
    > to make the frame requires that a 2" downtube is used to make the bike last long enough under
    > every conceivable condition, it is going to ride differently than a 1.125" diameter tube of
    > another material. Maybe that's where the discussion is going wrong...

    Do the math. If you can't, hire an engineer.
     


  2. Mike S.

    Mike S. Guest

    "Peter Cole" <[email protected]> wrote in message
    news:[email protected]...
    > "Mike S." <[email protected]> wrote in message news:[email protected]...
    > >
    > > How can you sit there and tell me that the shape/diameter of a tube
    doesn't
    > > affect its ride? If a 1" tube is x stiff, a 2" tube is 8x stiffer, that won't affect ride
    > > quality? If the material used to make the frame
    requires
    > > that a 2" downtube is used to make the bike last long enough under every conceivable condition,
    > > it is going to ride differently than a 1.125" diameter tube of another material. Maybe that's
    > > where the discussion is going wrong...
    >
    > Do the math. If you can't, hire an engineer.
    >
    What math? If a tube is 8x more resistant to lateral stress, it is 8x more resistant to lateral
    stress. Just because I don't know the math, doesn't make it any less stiff laterally. Lateral
    stiffness is a component of how a bike rides, right? Oh, wait a minute, that would be position,
    geometry, wheels, saddle, THEN frame stiffness. Got it. How silly of me!

    Oh, and are these the same engineers that engineered the Tacoma Narrows Bridge? Talk about not
    taking vibration/harmonics into account!

    Mike
     
  3. Peter Cole

    Peter Cole Guest

    "Mike Jacoubowsky" <[email protected]> wrote in message
    news:m52da.2035$2%[email protected]...
    > > Bicycles are machines, simple ones at that.
    >
    > Again, I disagree, in the same manner as the person who was equating all violins as being
    > essentially the same. And yes, I have a background in music as well. Certainly not my chosen field
    > however.
    >
    > > The human sense of hearing evolved to discriminate extremely subtle features in sound, a musical
    > > instrument like a violin is capable of expression over the enormous range
    > of
    > > human sonic perception.
    >
    > ??????? The human sense of hearing has de-evolved. A dog's hearing is probably better suited to
    > the subtle nuances of a violin (not that a dog could understand its beauty).

    Human hearing has evolved to support speach, it is likely this same sohisticated mechanism that
    underlies musical appreciation.

    "Harsh" frames, if such things did exist, would only give you more jiggle at your butt, an annoyance
    perhaps, but clearly the absense of which doesn't constitute a religious experience.

    >
    > By the way, please point out to me where people have *measured* the differences in sound between
    > an ordinary violin and a Stradivarius. I'd be very interested in the analysis.

    I couldn't care less if there's any difference between violins, a bike frame is not a violin, it's a
    tubular truss designed to support the wheels and the rider's weight. It's as utilitarian as a
    kitchen chair. If somebody wants to pay a lot for highly formed tubing of high strength alloys, or
    the equivalent in fiber and resin, fine, you're just pushing the strength to weight curve out a
    little farther. Other than that, the bicycle frame hasn't changed since the turn of the century.
     
  4. Peter Cole

    Peter Cole Guest

    "Mike S." <[email protected]> wrote in message news:eek:[email protected]...
    >
    > "Peter Cole" <[email protected]> wrote in message
    > news:[email protected]...
    > >
    > > Do the math. If you can't, hire an engineer.
    > >
    > What math?

    The math that tells you how much your butt is going to jiggle itself sore less from the frame
    soaking up all those nasty bumps. You know, the difference in compliance between a "sweet" and a
    "harsh" frame.

    > Lateral stiffness is a component of how a bike rides, right?

    Not a particularly large one. Some feel it degrades high speed handling, some complain about BB flex
    and front derailer rubbing. I've experienced the lattter, not the former. There don't seem to be any
    really major effects of lateral stiffness on "how a bike rides".

    > Oh, and are these the same engineers that engineered the Tacoma Narrows Bridge? Talk about not
    > taking vibration/harmonics into account!

    Bikes can oscillate, it's called "shimmy". It doesn't seem to be completely understood. It may be
    influenced by lateral/torsional stiffness of the frame. I haven't heard a manufacturer or cyclist
    claim that their frame material prevented shimmy. Now that would be an interesting and novel
    claim. The one about preventing butt fatigue just doesn't seem either believable or that
    interesting, if your butt gets sore, just buy one of those sprung saddles. They've been available
    for around 100 years.

    The Tacoma Narrows bridge failure wasn't about materials, so I don't understand your point, unless
    it is that engineers can be wrong. Well, that's a shocker! But a lot of bridges have been built
    since then, and most, I believe are still standing. Bicycle frames never had the mystique of
    suspension bridges, at least not since the '80's (1880's).
     
  5. Mike S. <[email protected]> wrote:

    > It feels like we're pushing down on the crankset, but I'd bet that we are pushing down and in
    > towards the BB. Seems to me that the BB is always moving around slightly in small circles. ... We
    > have two power strokes per revolution causing the bb to move slightly sideways relative to the
    > plane of the bike frame. Since you're bending the tubing laterally, it is no longer purely in
    > compression, right? If the tubing is no longer purely in compression, wouldn't it stand that there
    > could be flex along the length of the tube?

    > As I stood and sprinted on my SL steel bike I could watch the BB move laterally 1-2cm. I know I
    > was fascinated by this, sometimes to the detriment of my sprint. Most of the movement was when the
    > cranks were at their 3 o'clock positions on both sides.

    Yes, the BB shell is torqued by the pedaling action, and the BB shell-chainstay triangle will be
    twisted side to side. This is why when frames break it is often at the chainstay-BB junction - not
    from a sudden hit, but fatigue from millions of pedal strokes. I think most people in this thread
    agree that the frame can have meaningful side to side flex, not so much up and down.

    However, I really doubt the BB can move 1-2cm side to side. When you're riding the bike, you don't
    have a fixed point of reference to see which pieces are actually flexing. I think it would take an
    enormous force to distort a frame that much, and if you did bend it 1-2cm, it would take a permanent
    set. This is how they make steel curved forks and cold set rear triangles, after all. If the BB did
    move that much, you'd have the front derailleur causing the chain to throw, and the cranks knocking
    into the chainstay (I have steel bikes with non-oversized tubing like SL and only 1cm clearance
    between right crank and chainstay). and 1 cm or less clearance.

    We've all had the chain rub while sprinting or standing, and that is closer to a couple of mm of
    side-to-side motion, much of which is in the BB spindle and the chainrings.

    > Like I said in one of my earlier posts: I'm not sure what makes a bike ride differently from one
    > material to another, but there's got to be something going on that isn't being addressed by the
    > "stiffness test."

    > I would similarly bet that steel and Ti are non-linear when it comes to reacting to small inputs
    > while AL reacts fairly linearly to the same inputs. Anyone done any studies on this? I'm willing
    > to be convinced, but it'll take some real doing, rather than just saying "I'm an engineer and
    > that's what I say is true."

    Most forces on a frame are in the linear regime for steel, Ti, or Al. That is if you put X weight on
    it, it moves 1mm, and 2X moves it 2mm. Damon Rinard's tests assume this. The amount of movement per
    applied force is the Young's modulus of the material; physics courses sometimes have a lab where you
    measure Young's modulus by hanging weights on a length of metal rod. This is elastic deformation
    (the metal returns to its initial shape), as opposed to plastic deformation, when it takes a
    permanent bend. You can see this happen with a piece of metal, even a paperclip - it springs back
    from small forces but push hard enough and it's bent for good. There is a threshold, which is
    related to the tensile strength of the material.
     
  6. "Mike Latondresse" <[email protected]> wrote in message > >
    > Hey Fab you have been working ths whole off season (plus half of the training one too) so what
    > bike hae you bought to relplace the CAAD2 you where riding???.

    Well, Me, Erik Zabel and the rest of the team Telekom crew have each been supplied with six custom
    built Pinarello Prince LS frames for the 2003 season. They are from the Treviso shop and Fausto
    Pinarello assures me the Dedacciai --X1X tubing we're using is half a pound lighter that the SC
    61.10A tubes used for the standard Prince frames that guys like you get stuck with.

    I tell you something, Me and Andreas Kloden are really doing these top frames justice at the Tirreno
    - Adriatico right now.
     
  7. > Sorry I couldn't give you some solid citations. I'll ask for that japanese site at a cello forum I
    > hang out on. If and when I get it I pass it along here.
    >

    Thanks, I figured that somebody, somewhere, had done the sort of things you mentioned. How does
    Strad magazine approach all of this? Do they come at it from a cynical, or should I say, clinical
    point of view, or are they something like the Bicycling of the music world, doing what they can to
    pump something up, regardless of merit?

    --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
     
  8. helen

    helen Guest

    In article <[email protected]>, Mike Jacoubowsky
    <[email protected]> wrote:

    > > Sorry I couldn't give you some solid citations. I'll ask for that japanese site at a cello forum
    > > I hang out on. If and when I get it I pass it along here.
    > >
    >
    > Thanks, I figured that somebody, somewhere, had done the sort of things you mentioned. How does
    > Strad magazine approach all of this? Do they come at it from a cynical, or should I say, clinical
    > point of view, or are they something like the Bicycling of the music world, doing what they can to
    > pump something up, regardless of merit?
    >

    I lied about the japanese site. I found it again at www.minehara.com but while there is some wave
    analasis it isn't really germaine to the discussion at hand (bikes or violins). The Strad Mag series
    is clinical and is dedicated to furthering the quantifying of that which has till now been ascribed
    to magic and voodoo by people who call engineers "arrogant chip supports."

    I'm no enigineer but the arguments from both sides has made me want to shout: "SHUT UP AND RIDE THE
    FREAKING BIKE--ANY BIKE. JUST SHU UP ABOUT IT ALL READY!" However if pressed to take a side, I'd
    answer with this quote:

    "Until you can measure something, you can never truly understand it."

    Lord Kelvin
     
  9. > "Until you can measure something, you can never truly understand it."

    Whatever it takes to make someone ride more (a *measurable* qty!), that's the most important thing
    about a bike. Any bike. Could be color. Could be how much it costs (or how little). Could be the
    sound it makes, or a perception that there's something about the way it feels that one likes. Or all
    of the above. Or none! But the right bike is the one that you just can't pass up in the garage or
    bedroom or wherever, without wanting to ditch your other responsibilities and go out for a ride.

    --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com
     
  10. In article <[email protected]>,
    Mike Latondresse <[email protected]> wrote:

    > Ryan Cousineau <[email protected]> wrote in news:rcousine-
    > [email protected]:
    >
    > > http://www.sfu.ca/~rcousine/bike/tshirt.jpg
    >
    > Hey tell us more...when did this happen?

    The Ides of March. On one hand, not impressive, because I was in the "recreational" division, which
    was me, 38 frat boys on MTBs, and two frat boys on real road bikes. But the frat boy who hung with
    me to the end was reasonably strong, and in the end I outrode him.

    It was fun: 1.5 km course with a semi-serious climb (definitely not an industrial-park crit) and the
    start-finish halfway up the climb. The other rider was a tad stronger on the climb, but I seemed to
    gap him every time on the flats and the descent. So on the final lap, I followed him up the climb,
    turned on my sprint as soon as we crested the hill, and dropped him right there. It may have been a
    criterium of two, but we had a serious, straight race, and we both gave our all. He was gracious in
    defeat, and I think we both had fun.

    Honestly, I didn't expect such weak competition, since there actually was a fat-tire race scheduled
    as well. The "competitive" riders (Cat
    5/4/3) would have eaten my lunch, but if I had known, I probably would have done that race instead.
    But it was my first race ever, so from now on I'll ride as a Cat 5 in the local weekly series
    (World Tuesday Night Championships at UBC).

    Think I should wear the t-shirt to my next race?

    --
    Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club
     
  11. Mike S.

    Mike S. Guest

    All right. Since y'all are bound and determined to try and prove me wrong, please define "the ride"
    of a bike, and the relevant criteria involved. Please use small words, since I am from VA...

    I'll postulate that "the ride" of a bicycle is a result of the interaction between the rider, the
    frame, the wheels/tires, and the road. The ride of a given bike cannot be measured without taking
    into account the rest of the system.

    I will further postulate that the ride of the frame is independent of what wheels/tires, fork, etc.
    that are mounted on the frame. You can either add to or subtract from relative comfort of the system
    by changing components, but it has nothing to do with the way a frame reacts to inputs.

    So, please explain in small words, how changing geometry is going to affect the ride of a frame,
    since all frames' have approximately the same stiffness vertically. Seatstays, being in compression
    and all...

    Ditto with fit, since all fit does is affect relative comfort, not how the frame reacts to inputs.

    Or is "the ride" so subjective from one person to another that it can't be measured? Marketing
    aside, there HAS to be something that isn't being taken into account. When I can transfer the same
    components from one frame to another and be able to tell that one frame rides differently (with the
    same components!) than the other, and without any preconceived notions, y'all aren't doing the right
    tests or something. No, I'm not smoking crack, my two steel road frames (with the same parts!) ride
    differently.

    I'm not trying to say anyone's wrong. I'm just trying to prove that if you're testing for the wrong
    thing, you get the wrong answers. I haven't a clue what the "right" test is, but it sure ain't what
    I've read so far.

    Mike

    "archer" <[email protected]_hotmail.com> wrote in message
    news:[email protected]...
    > I know Aluminum frames have had a reputation (deserved or not) of being stiff, and I'm wondering
    > if that's still true, with the different alloys they use now. My current bike is a 20+ year old
    > steel-framed Schwinn LeTour (a.k.a LeTank).
    >
    > I'm looking at a Specialized Sequoiah Expert or equivalent, and there seems to be a lot to choose
    > from in that range. Pretty much all the bikes in that price range seem to have aluminum frames
    > with carbon forks, and I'm curious how the ride might compare between the two (leaving the
    > suspended seat on this particular model out of the equation). The LeTour has 27 x 1.25, 85psi
    > tires, and the Sequoiah has 700 x 26c tires, but I don't know the pressure.
    >
    > Opinions, please?
    >
    > --
    > David Kerber An optimist says "Good morning, Lord." While a pessimist says "Good Lord, it's
    > morning".
    >
    > Remove the ns_ from the address before e-mailing.
     
  12. On Sun, 16 Mar 2003 00:26:04 -0500, Benjamin Weiner wrote:

    >> As I stood and sprinted on my SL steel bike I could watch the BB move laterally 1-2cm. I know I
    >> was fascinated by this, sometimes to the detriment of my sprint. Most of the movement was when
    >> the cranks were at their 3 o'clock positions on both sides.
    >
    > Yes, the BB shell is torqued by the pedaling action, and the BB shell-chainstay triangle will be
    > twisted side to side. This is why when frames break it is often at the chainstay-BB junction - not
    > from a sudden hit, but fatigue from millions of pedal strokes. I think most people in this thread
    > agree that the frame can have meaningful side to side flex, not so much up and down.
    >
    > However, I really doubt the BB can move 1-2cm side to side.

    I agree. While the bb will move side-to-side a few mm, 2 cm is huge. We used to check frames for
    stiffness by pushing on the bb with one foot, while holding the bike at the seat and the bars. You
    could see then a good cm or 2 of motion. However, most of this came from the tires. In order to get
    a good idea of how much the frame itself could flex, you'd have to attach bare hubs, clamp down
    those hubs to a rigid structure, then push side-to-side on the bottom-bracket.

    >> I would similarly bet that steel and Ti are non-linear when it comes to reacting to small inputs
    >> while AL reacts fairly linearly to the same inputs. Anyone done any studies on this? I'm willing
    >> to be convinced, but it'll take some real doing, rather than just saying "I'm an engineer and
    >> that's what I say is true."
    >
    > Most forces on a frame are in the linear regime for steel, Ti, or Al. That is if you put X weight
    > on it, it moves 1mm, and 2X moves it 2mm.

    In order to get a nonlinear response you would have to bend the material to the point of plastic
    deformation. That would not be good for the frame.

    --

    David L. Johnson

    __o | "It doesn't get any easier, you just go faster." --Greg LeMond _`\(,_ | (_)/ (_) |
     
  13. >Think I should wear the t-shirt to my next race?

    No, but I think you should save the T-shirt.

    --

    _______________________ALL AMIGA IN MY MIND_______________________ ------------------"Buddy Holly,
    the Texas Elvis"------------------
    __________306.350.357.38>>[email protected]__________
     
  14. "Jkpoulos7" <[email protected]> wrote in message mb->

    > It's true as ever. Ride any aluminum frame then ride a quality steel frame
    and
    > there is no doubt you'll feel the difference.

    Yea, the feeling you get is that there is a huge magnet at the base of evey hill and you're trying
    to ride away from it on this slug of a bike that's made out of the same stuff that the Golden Gate
    bridge is built of.

    Look, forget steel, it was ok back in the '80's but we've moved on. Women nowadays won't even look
    at a guy on something like a Columbus Nemo or Dedacciai EOM tubed frame.
     
  15. Jon Isaacs

    Jon Isaacs Guest

    >I will further postulate that the ride of the frame is independent of what wheels/tires, fork, etc.
    >that are mounted on the frame. You can either add to or subtract from relative comfort of the
    >system by changing components, but it has nothing to do with the way a frame reacts to inputs.

    Somethings to consider:

    As the rider you have no way to know whether it is the tires, the seat or the frame that is causing
    the ride to be as it is.

    You have made a hypothesis, now I ask, how are you going to test this hypothesis?

    The easiest way I can see it to change some of the variables like tires and seats, tire pressures
    and see if it does or does not make a difference in the ride.

    IN my experience, switching from say 23 mm tires to 28 mm is very noticeable, especially on rough
    roads. And of course the difference between say 700C x 23s and 26 x 1.5 inch tires is major. Of
    course the frame will be different between the 700C tires and the 26 x 1.5 tires. However it is
    interesting that a super stiff MTB frame will ride more smoothly than something with narrow high
    pressure tires.

    >Or is "the ride" so subjective from one person to another that it can't be measured? Marketing
    >aside, there HAS to be something that isn't being taken into account.

    Rather than depending on the rest of us to discover whether there is something else, just do the
    tests. You don't need fancy equipment to see whether or not changing the tires to larger sizes make
    large differences in the ride.

    Jon Isaacs
     
  16. Mike S.

    Mike S. Guest

    "Jon Isaacs" <[email protected]> wrote in message
    news:[email protected]...
    > >I will further postulate that the ride of the frame is independent of
    what
    > >wheels/tires, fork, etc. that are mounted on the frame. You can either
    add
    > >to or subtract from relative comfort of the system by changing
    components,
    > >but it has nothing to do with the way a frame reacts to inputs.
    >
    > Somethings to consider:
    >
    > As the rider you have no way to know whether it is the tires, the seat or
    the
    > frame that is causing the ride to be as it is.
    >
    > You have made a hypothesis, now I ask, how are you going to test this hypothesis?
    >
    > The easiest way I can see it to change some of the variables like tires
    and
    > seats, tire pressures and see if it does or does not make a difference in
    the
    > ride.
    >
    > IN my experience, switching from say 23 mm tires to 28 mm is very
    noticeable,
    > especially on rough roads. And of course the difference between say 700C
    x 23s
    > and 26 x 1.5 inch tires is major. Of course the frame will be different between the 700C tires and
    > the 26 x 1.5 tires. However it is interesting
    that
    > a super stiff MTB frame will ride more smoothly than something with narrow
    high
    > pressure tires.
    >
    Changing tires to a bigger size is not affecting the ride of the frame, it is merely adding to the
    comfort of the bike. Admittedly, there may be less road vibration coming through the ST, but the
    torsional stiffness, and rigidity of the frame is no different.

    Mike

    >
    >
    >
    > >Or is "the ride" so subjective from one person to another that it can't
    be
    > >measured? Marketing aside, there HAS to be something that isn't being taken into account.
    >
    > Rather than depending on the rest of us to discover whether there is
    something
    > else, just do the tests. You don't need fancy equipment to see whether or
    not
    > changing the tires to larger sizes make large differences in the ride.
    >
    > Jon Isaacs
     
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