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  1. #1
    Senior Member bernmart's Avatar
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    lugged versus welded steel frames

    A guy I was talking to a week or so ago insisted that a lugged steel frame has a softer, more compliant ride that a welded frame, all other things being equal. I'd always thought that the distinction between the two was largely aesthetic and about ease of repair.

    Was he right? In my experience cyclists often claim expert knowledge that they don't have, but still. . . .
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    Senior Member ftwelder's Avatar
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    There is really no answer to that question. It is my opinion that spoke count, tire pressure and handlebar width can make much greater changes to the ride quality of a bike than construction method. I like the look of lugged frames better but I also think some TIG bikes are hot looking. I have a really pretty Chris Chance.

    I do feel that brazed frames have less built in stress than TIG welded frames but are not at strong (or light). Higher ultimate failure strength does not make a better bike unless there is potential for failure while in use.
    1886 Surrey machinists Invincible, 1900 Nashua, 1937 Raleigh Golden Arrow, 1938 Raleigh Silver Record, 1951 Armstrong tourmalet, 1970 Motobecane Grand Record, 1971 Raleigh Professional, 1971 Gitane TDF, 1972 Legnano Gran Primio, 1973, Peugeot PX-10, 1975 Roberts, 1984 Battaglin Giro, 1985 Grandis Speciale, 2012 FTW

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  3. #3
    Randomhead
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    all things being equal, there is no way a lugged bike can be more compliant than a welded frame since the lugs add material. Heat cycles don't change the stiffness of tubes, they may change yield/ultimate strength which is something you don't want to test.

    This is the sort of discussion where it's best to nod in agreement and back away slowly.

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    There is no difference...........once the tubes are rigidly hooked together they all behave the same and will give the same ride.

    Dave

  5. #5
    Senior Member bernmart's Avatar
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    As I suspected. Thanks, guys.
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    beermart - I think I also in agreement with the other responders... To actually achieve a technical response one would have to perhaps round up two identical tubesets that are both lug and TIG-able; build one up with lugs and TIG up the other one, keeping every bit of the design identical. Then build each of the frames up with identical components, wheels, etc., and have them ridden by the same rider multiple times across multiple days. Then a survey of that rider might yield some specific opinions one way or the other.

    The opinions wouldn't be technical...one would need to subject both frames to a instrumented stress tester or what not. I wouldn't be surprised in the end if the riders' view was opposite to what the stress testing revealed... And also betting that one could flip the riders view by doing little more than changing one of the bikes, such as adding 5psi to the tires or switching to a different saddle or bar wrap or changing the crank arms by a few mm's... fwiw; /K

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    Been hanging out with the vintage crowd at the Rose Bowl ride? Some of those guys have such weird opinions that I suspect they're just pulling legs to get a reaction.

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    Quote Originally Posted by Six jours View Post
    Been hanging out with the vintage crowd at the Rose Bowl ride? Some of those guys have such weird opinions that I suspect they're just pulling legs to get a reaction.
    You mean the one early each month? I avoid that one.

  9. #9
    Senior Member longbeachgary's Avatar
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    Quote Originally Posted by bernmart View Post
    In my experience cyclists often claim expert knowledge that they don't have, but still. . . .
    Well yeah!!!

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    Quote Originally Posted by repechage View Post
    You mean the one early each month? I avoid that one.
    Yeah, first Sunday of every month. There can be some incredible bikes out there but the company can be hit-or-miss. Sometimes they're a pleasant, safe group. Other times they aren't. C'est la vie, I suppose.

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    Quote Originally Posted by ksisler View Post
    beermart - I think I also in agreement with the other responders... To actually achieve a technical response one would have to perhaps round up two identical tubesets that are both lug and TIG-able; build one up with lugs and TIG up the other one, keeping every bit of the design identical. Then build each of the frames up with identical components, wheels, etc., and have them ridden by the same rider multiple times across multiple days. Then a survey of that rider might yield some specific opinions one way or the other.

    The opinions wouldn't be technical...one would need to subject both frames to a instrumented stress tester or what not. I wouldn't be surprised in the end if the riders' view was opposite to what the stress testing revealed... And also betting that one could flip the riders view by doing little more than changing one of the bikes, such as adding 5psi to the tires or switching to a different saddle or bar wrap or changing the crank arms by a few mm's... fwiw; /K
    I agree that testing is more scientific, but it shouldn't really require a test to determine if identical tubes and geometries where the joint areas are doubled on the lugged frame are stiffer than ones where the joints are almost naked. It probably would take extensive testing to determine if the lugged frame being stiffer was enough stiffer for the ride difference to be noticeable. And whether it would be noticeable in all potential tire and geometry set-ups. Or it might be the case that because tube deflection is minimal in many cases that the lug related increase in stiffness would not have any effect on compliance, since that might just be vibe. But I see no basis for the idea that the lugged frame would be more compliant in any real sense. That seems pretty evidently untrue.

    Where the lug crazies normally go is to some specification they say can be only achieved with lugs, then you get ride advantages because the tubes are different so the story goes. Today I am not sure what spec that would be. Lugs are cool, but that was about it.

  12. #12
    Senior Member bernmart's Avatar
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    Quote Originally Posted by Six jours View Post
    Been hanging out with the vintage crowd at the Rose Bowl ride? Some of those guys have such weird opinions that I suspect they're just pulling legs to get a reaction.
    I have ridden with those guys, but the opinion that I was asking about comes from a retired engineer, and is thus offered with an air of authority. Thanks for all these replies; I've enjoyed them.
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  13. #13
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    Quote Originally Posted by bernmart View Post
    I have ridden with those guys, but the opinion that I was asking about comes from a retired engineer, and is thus offered with an air of authority. Thanks for all these replies; I've enjoyed them.
    I suspect that air was quite hot...
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  14. #14
    Senior Member bernmart's Avatar
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    Quote Originally Posted by David Tollefson View Post
    I suspect that air was quite hot...
    You got it!
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    coprolite fietsbob's Avatar
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    Basically..


    Lugged joints have a similarity to soldering Pipe together , the solder flows into the gap , between ,
    drawn towards the heat source, capillary action, .. aided by the fluxed & cleaned surfaces.
    like wise the Brass and silver solders.

    the heat affected ends of the tubes is often less with TIG, but top frame tubesets
    are designed to return to adequate strength with a slow air cooling.

    Its part of the function of tube Butting, too, thicker wall on the ends..
    Last edited by fietsbob; 03-05-13 at 05:17 PM.

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    Late to the party but IMO this is a very simple question with a simple answer: the lugged frame will be very slightly less compliant. There is more material at the joints and the heat doesn't change the stiffness of the materials one whit. The comparative softness of the brazing alloy is not germane; if the joint is properly constructed the brazing material is subject to plastic contraint.

    I do not believe that the tiny difference would be detectable.

  17. #17
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    +1. The exception being if our model is right. The model that says, I assume, compliance would be the effect of tubes bending individually, even when the structure is triangulated. That is basically where I am at, but it does sound a little dubious. I just know from a lot of other gear, that often the effect is more in the order of music, vibration, etc... Or sometimes the perceived effect is picked up by hearing. We don't really know if the thing is imperceptible, or if perceivable, how.

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    After a couple of big experiments I am increasingly confident that a lot of what we call "ride quality" is as you say, an acoustic phenomenon.

    A lugged and a welded joint sound different. Whether that makes any difference to ride quality I can't say.

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    This sounds like a wine debate about expensive wine versus cheap wine. I love when the experts pick the Trader Joe wine over some really expensive wine after ballyhooing about their credentials. Engineers can be the worst when discussing things like this. I always reference anyone that proclaims they are an engineer to the skinny bridge and the Titanic.

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    Randomhead
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    I'm an engineer, what are you trying to say?

    I usually stay out of these kinds of conversations IRL, nobody wants to pay my consulting rates for some reason.

  21. #21
    Andrew R Stewart Andrew R Stewart's Avatar
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    Quote Originally Posted by unterhausen View Post
    I'm an engineer, what are you trying to say?

    I usually stay out of these kinds of conversations IRL, nobody wants to pay my consulting rates for some reason.

    Yet you give out advice here for free... Andy.

  22. #22
    THE Materials Oracle Falanx's Avatar
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    Quote Originally Posted by cresap View Post
    This sounds like a wine debate about expensive wine versus cheap wine. I love when the experts pick the Trader Joe wine over some really expensive wine after ballyhooing about their credentials. Engineers can be the worst when discussing things like this. I always reference anyone that proclaims they are an engineer to the skinny bridge and the Titanic.
    Blame Procurement for the Titanic. The ******** bought pig-iron, the steel was so dirty.

    Otherwise Mark's spot on. As is Frank on handling :-)
    "While my father fought for you, I learnt. While my father glorified your petty administration, I learnt. While he longed every day for our line, Adun’s line, to be restored, I learnt. He sent me away to bring the Dark Templar back when the time was right!
    "And you tell me that I cannot do this? That I cannot feel the weight of the universe?
    "Damn you, Tellan! Aldaris killed my father!"

  23. #23
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    Quote Originally Posted by cresap View Post
    This sounds like a wine debate about expensive wine versus cheap wine. I love when the experts pick the Trader Joe wine over some really expensive wine after ballyhooing about their credentials. Engineers can be the worst when discussing things like this. I always reference anyone that proclaims they are an engineer to the skinny bridge and the Titanic.
    Were your other three posts of the quality of this one?

    I'm one of the few people you'll meet who has done formal tertiary level training in both engineering and wine judging* and I find your post ridiculously wide of the mark.

    * Yes, there is such a thing: AWRI Advanced Wine Assessment

  24. #24
    THE Materials Oracle Falanx's Avatar
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    Quote Originally Posted by Mark Kelly View Post
    Were your other three posts of the quality of this one?

    I'm one of the few people you'll meet who has done formal tertiary level training in both engineering and wine judging* and I find your post ridiculously wide of the mark.

    * Yes, there is such a thing: AWRI Advanced Wine Assessment
    \m/


    That is all
    "While my father fought for you, I learnt. While my father glorified your petty administration, I learnt. While he longed every day for our line, Adun’s line, to be restored, I learnt. He sent me away to bring the Dark Templar back when the time was right!
    "And you tell me that I cannot do this? That I cannot feel the weight of the universe?
    "Damn you, Tellan! Aldaris killed my father!"

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