Tuesday, November 2, 2010

Lugged Non-Steel?

[image via the IF Blog]

I have been curious about bicycles that are lugged, but not made of steel. The first ones I noticed were the lugged carbon fiber frames made by our local Independent Fabrications. I have seen a couple of these in person, and they are beautifully done. The picture above is a detail from the XS model. The lugs are painted titanium, over a clear-coated carbon fiber frame.

[image via the IF Blog]

Here is a detail shot of a cyclocross model where both the lugs and the frame are carbon fiber.

[image via the IF Blog]

And here is a Corvid model frame, from a bicycle built for Boston Celtic Ray Allen - the carbon lugs painted a metallic Celtics green. The lugs on the Independent Fabrications bikes are molded to incorporate the stylised crowns in the company's logo, so the look is especially striking. 

[image via Alchemy Bicycles]

Though I have never seen their frames in person, Alchemy Bicycles seems to be doing something similar - carbon fiber frames with aluminum lugwork. 

[image via Bruce Gordon]

And Bruce Gordon takes it one step further by making his titanium-lugged carbon fiber frames look like true classics. 

Reading the manufacturers' descriptions of the construction, I am wondering how IF and Alchemy integrate the lugs with the frame. I am nowhere close to knowledgeable when it comes to these manufacturing techniques, but don't the lugs run the risk of making the infamously brittle carbon fiber even more so? Is a lugged carbon frame "safe"? And is there any purpose, other than decorative, to lugging these frames? After all, I had thought that the very benefit of carbon fiber construction, was that it enabled the frame to be built in a single mold.

[image via aj_the_first]

But carbon fiber is not the only non-steel material being used in lugged bicycle construction. The above detail is from a wooden Porteur made by a small frame builder.

[image via aj_the_first]

The lug sleeves here are parts of actual lugged tubing, the lugwork rather elaborately done. Have a look at the flickr pictures that show his process - it's fascinating.


And a lugged faceted frame, made by Sylvan Cycles out of composite wood. The faceted tubing reminds me of this vintage lugged aluminum Caminade bicycle I wrote about earlier. It must feel interesting to ride a faceted bike. I have never heard of Sylvan Cycles before, but apparently they are made in Massachusetts. Amazing how many interesting local builders there are in our vicinity. 

[image via antbikemike]

And speaking of local builders and wooden tubing, I still can't get over the antique wooden showbike by ANT

[image via antbikemike]

The lugsleeves are copper-plated steel and they were designed to attain the aged look - which makes this bicycle seem wonderfully "alive" to me. 

But, same as with carbon fiber, I am wondering whether these wooden bicycles are truly ridable, and what effect the lugwork has on them structurally. Does it improve things, or is it mainly there for the "wow" factor? I would love to try a lugged wooden bicycle or a lugged carbon fiber bicycle some time, and would be interested to hear from those who have ridden one. These construction methods do not receive a great deal of attention, but they are certainly intriguing - and beautiful.

31 comments:

  1. How about Bamboo?
    The Bamboo Bike Project is a project by Scientists and Engineers at The Earth Institute, Columbia University, and aims to examine the feasibility of implementing cargo bikes made of bamboo as a sustainable form of transportation in Africa.
    http://bamboobike.org/Home.html
    You can even sign up to build your own:
    http://bamboobikestudio.com/go/

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  2. High end racing bikes have been made with lugged carbon fiber construction for many years now. Indeed, with the advent of carbon fiber monocoque frames, the lugged ones are have become somewhat passe. Colnago's EPS and C59 Italia models are good examples of this genre.

    Trek and Specialized also made lugged carbon frames in the '90s, including the Trek 2300 Pro and the Specialized Allez Epic. My understanding is that these frames tended not to be especially reliable, and they are nowadays rarely seen.

    Of course, none of these mass market bikes are nearly as beautiful as the custom built ones you mention!

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  3. Sam - I sorta knew that, but thought that the new ones were the "new wave" after the passe-ness of the originals had in itself become passe? : )

    Do you know whether there is any difference between the way the old ones were manufactured and the way these are manufactured now?

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  4. I don't know for certain, so I am certainly up for being corrected, but I think the manufacturers pour or coat the inside of the lugs and the tube ends with some sort of super strong epoxy, which would act the same as silver or brass in a brazing process. The lugs allow greater epoxy to structural material contact.

    Personally, I wouldn't ride any carbon fiber bike, just because I see them as being the 80's Oldsmobiles of the cycling world- designed with built-in obsolescence. Part of the reason that you don't see a lot of the older carbon fiber bikes is that they simply don't last as long as bikes made from steel or even aluminum. They are built for light weight and speed more than they are built for longevity.

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  5. Rather than prompt a brittle failure of the carbon, the danger with the lug is that it is difficult to get proper bonding pressure to the joint to ensure a strong bond. The joint is also not as strong for its weight as a less elegant scarf joint cured in one shot.

    Many manufacturers use lugged carbon. Usually, as they understand the material better, they move beyond lugs - unless they're doing lugging for its decorative aspects. If I were building a carbon bike, I'd eschew lugs. If a steel bike, I'd embrace them.

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  6. There's a great article in the newest Bicycle Quarterly:
    http://www.vintagebicyclepress.com/currentissue.html

    It's an interview with Bruce Gordon specifically about "how he made a classic bike almost entirely from titanium and carbon fiber". He explains pretty much everything except how the two materials are properly connected. He says it's a trade secret, but i would imagine some sort of super polymer is used. Either way, beautiful and very pricey result!

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  7. Here is a lovely example of a wooden tubed, lugged bike: http://www.flickr.com/photos/aj_the_first/sets/72157624758647268/

    It was an experiment for Andrew, the frame builder, but he says he is pleased with the results. Apparently it's a bit soft, but very rideable!

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  8. Velouria, thank you for including my wood bike in this post :)
    My bikes lugs were made of steel and then copper plated. I used the same glue/epoxy that IF uses for their Ti/Carbon bike.
    As already pointed out,the lugged/glued method has been in use for a very long time [Exxon Grafite and Vitus frames]. The biggest issue was the glue getting old and letting loose. New epoxy glue has improved this very much, but only time will tell if they really work.
    The wood bike I made was really unrideable. I did ride it myself and then sold it to a collector as an art piece.
    The new wood and bambo bikes are are very usable, but I have never ridden one.
    I consider all of these bikes to be lugged or any bikes that has these pipe fitting designs.

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  9. There was a gorgeous carbon and polished SS lugged frame at Open bikes when we had that BRW meeting there. I've been sad ever since that I didn't check into the cost and the geometry of it to see if it was something that I could justify bringing home with me.

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  10. Lugged carbon fiber doesn't make a whole lot of sense, now that carbon fiber frames can be made in one piece. The "monocoque" (or "unibody") carbon frames are stronger and lighter than the older lugged frames, and allow manufacturers more options in shape and aerodynamics.

    Lugged construction for wood or bamboo-tubed bikes is the best way to go; metal lugs are stronger than wood and allow a good way to attach different wood tubes together. However, I would worry about the durability of wood or bamboo over the long-term. You wouldn't leave a wood bike outdoors all year round.

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  11. Renovo makes all-wood frames. Some of them are breathtakingly beautiful. Materials include, but are not limited to, bamboo, and according to Renovo some of these bikes rival aluminum and/or titanium in weight. Also, not cheap. I have no personal experience with them but I love the concept.

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  12. I ride an old carbon Look with skinny carbon tubes glued into aluminum (I think) lugs. I believe this method allows them to use one set of lugs and make different frame sizes by simply choosing longer or shorter tubes as opposed to the more modern styles that require a different mold for each size frame.
    Kinda funny that my carbon bike is lugged, but my steel bikes aren't!

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  13. cycler - I remember that frame at Open; wish I had taken some pictures.

    Andy Mangold - of course, the wooden Porteur! I've included it; that is a stunning bicycle.

    I would probably not ride a carbon fiber bike myself for a number of reasons, unless in some fantastic scenario I became a bicycle racer and was required to ride a CF bike. But the construction still interests me, especially if it looks aesthetically appealing and labor intensive.

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  14. "Lugged construction for wood or bamboo-tubed bikes is the best way to go; metal lugs are stronger than wood and allow a good way to attach different wood tubes together"

    Um, not so much for at least two reasons.
    1. Bad engineering to use a stiff lug (steel,carbon) to join less stiff materials like wood or bamboo. The tubes will fail at the intersection of joint and tube due to concentration of repeated bending loads there.
    Calfee, who restarted the bamboo thing, found that out with his bamboo frames and quit making carbon lugged bamboo frames.
    2. Wood/bamboo shrinks and expands with moisture change, it can't be prevented with conventional finishes. The expansion in a rigid connector will exceed the proportional limit of the expanding material, then when it shrinks back, it will be smaller. As that cycle repeats, the joint will become loose, which on a bike frame isn't ideal.

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  15. Kenster said...
    "...Bad engineering to use a stiff lug (steel,carbon) to join less stiff materials like wood or bamboo. The tubes will fail at the intersection of joint and tube due to concentration of repeated bending loads there.
    ...Wood/bamboo shrinks and expands with moisture change, it can't be prevented with conventional finishes."


    That is what I was thinking. What if anything are the framebuilders doing to overcome these issues?

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  16. Think of lugs as permitting a wide range of custom fits, versus the numerous layup schedules of a monocoque frame.

    Jim

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  17. Kenster- I would guess that they would use some sort of process to make sure that the material was shrunk as much as possible when it was assembled, and even then assembled with as tight a fit as possible. That way, expansion would just make it tighter, and reshrinkage wouldn't be an issue. Again, this is just a guess.

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  18. The father of your Sam Hillborne would NOT approve of these construction materials :).

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  19. Ok, the picture of the lugged faceted wood frame by Sylvan Cycles looks to me like it should have a #2 printed on it. Maybe it's just the way it's lit. Those lugs on the carbon fiber frame in the 2nd photo just rock my socks. They look like they're melting and blowing back in the wind.

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  20. JP Twins - Thanks for the link to Bruce Gordon, I have included a picture of his work. Oh, and I need to start subscribing to Bicycle Quarterly. I just think if I do it'll really be the end of any pretense of sanity on my part : )

    Anon 7:56 - He would not indeed! I don't even think he approves of titanium tubing.

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  21. "That is what I was thinking. What if anything are the framebuilders doing to overcome these issues?"
    Thing is, the expansion/contraction can be slowed, but not stopped, at least not by acceptable coatings, so maybe the builders can just say their frames have a limited life and be done with it, but then how can they prevent catastrophic failure at some point? Just through-bolt the connection, which is what was done in the 1890's with lugged frames of wood and bamboo... but then you get a noodly bike when the joint loosens.

    For the stress concentration problem at the joint, Calfee started using hemp fiber instead of carbon, which seeems to work, but the matrix has to approximate the flexibility of bamboo, which is not at all stiff. So once again you have a noodly bike. But that may be ok for some folks.

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  22. Kenster- Perhaps the inside of the lugs are threaded? Again, just speculation, but I would think that threading the inside of the lugs as well as the wood, when combined with a strong epoxy, would prevent much damage from expansion or contraction.

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  23. Fiber reinforced plastics are great things, but using tubes and lugs with these kind of materials makes me scratch my head.

    Why are the stresses not being engineered to be spread along longer distances, to take advantage of the tensile strengths of these fibers?

    Carbon, especially, has very little advantage when used in such modulus intensive shapes - it performs best in long sheets, like airplane wings.

    It's often paired with Kevlar to improve it's "flex" - as carbon will "snap" like a window pane when bent.

    Why doesn't a someone make a bike that's a skinned triangle with rigidized verticies?

    A lightweight injected foam could give the form enough impact resistance.

    Lugs only compute where steel meets steel, in my opinion.

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  24. With the exception of the Bruce Gordon bike, all of the steel or Ti lugs are significantly longer than those used in steel/steel construction which provides a greater bonded area and shortens the carbon "lever" that would cause weakening at the end of the lug. Also, the stiffness and especially the durability of CF tubing are significantly greater than in the days of the Trek 2300 and similar bikes. Stems, handlebars, and cranks are being made of the stuff for pro-cycling's strongest sprinters as well as for abusive DH riders.

    Worries of catastrophic failure, while not invalid, are not as relevant as back when Grant Petersen staged a steel vs. carbon sword (fork) fight. Of course, the stuff still breaks (check out bustedcarbon.com), but I've broken 2 crank arms, 3 handlebars, a stem, one frame, and 2 forks, but none were CF. All were aluminum except the frame and forks, which were steel. Everything breaks (though you will likely be pleased to know that 2/3 of the steel breakages propagated slowly enough for me to notice during routine maintenance, whereas all of the aluminum failed rapidly).

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  25. Carbon fibre is notorious for failure. check out www.bustedcarbon.com for a laugh or not a laugh if it's you riding the bike!
    Carbon fibre freaks me out.
    And it's one of those things, striving to be better than what was already great and perfect.
    Bamboo is interesting as it is strong, but would it hold together as a bicycle? my husband wants one.

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  26. Anon 12:39 - Oh yes, I know. This whole website is mostly an ode to lugged steel. But sometimes alternative methods of construction are interesting - especially if they incorporate some degree of craftsmanship and uniqueness. One of the several things I dislike about CF is that it looks "dead" to me, just very cold and clinical. But when I saw the IF lugged Corvid at a local bike shop, it looked alive and vibrant; it looked human. So that is what interests me about the bicycles I have showcased in this post - both the CF and the wooden ones.

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  27. Functional bikes are torsionally stiff, art bikes don't have to be. Some materials, like wood and bamboo, and aluminum, for that matter, are not torsionally stiff, which the first alum bike makers discovered when they merely copied the tube diameters of steel, which is much stiffer. Both Cannondale and Renovo solve the problem the only sensible way, they make their tubes large enough to achieve the stiffness they want, and of course Renovo avoids the whole lug problem by using wood-to-wood joinery of the highest caliber and strength. The small diameters necessitated by steel tubing-sized lugs, aren't even close to large enough to provide a torsionally stiff frame using wood or bamboo. But if style outweighs function for you, they do look very cool.

    Regarding carbon frames, carbon isn't the problem at all, it's the weight weenies needing to ride a bike like Lance's. You can have an extremely durable carbon frame, but it has to weigh more than 2.2 pounds. Next time you're in the LBS, flex the downtube walls of a Cervelo or similar, they're paper thin. But that's what carbon does better than the other materials; it's extremely torsionally stiff because the fibers can be precisely oriented to the load paths, and since the tensile strength of carbon is so much higher than the other materials, less material is need for stiffness, so you get a 2.2 pound frame that's stiff as hell. It just breaks easily because there's not much material there.

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  28. This post inspired me to look at these space-age bikes and Seven's web site. Cool. Seven has Ti frames in the ~3 lbs range. They even have a steel frame that's around 3.6 lbs. I mean, how important is it to save 1-1.5 lb on frame weight? Do you end up with a bike that's 15-16 lbs instead of 17 lbs if you use light-weight-everything components? Do you then only use a water bottle that's half-full?

    I sound like a "reverse-weight-weenie" for sure, but with everything else on the bike amounting to the majority of the weight, saving 1 lb in the frame itself at the potential cost of it cracking in half seems absurd for those of us who cycle for pleasure or compete at amateur levels. If your races appear on TV and someone buys a new bike every time you climb on it (or fall off of it), I suppose it makes sense to ride a 16-lbs-single-purpose-bike since you're going to be judged on fractions of a second to the finish line.

    It also makes sense if you collect racing bikes or just want to own expensive/exclusive bikes for pleasure reasons. I suppose it _also_ makes sense if the only way you can get yourself to cycle is by riding one of these bikes, otherwise you feel bored. The common theme here is doing what you like, not what "makes sense." That's fine.

    But for actual cyclists who aren't driven to the start line in a team car, these materials don't make a whole lot of sense IMO. Though, it's good to know that these bikes can be made to look beautiful.

    I really enjoyed seeing this post. :)

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  29. The wooden porteur from Dapper Cycles just knocked me out! I've been daydreaming about such a thing for years now, but I have none of the requisite skills for making one. And now you show me that such a thing exists! I'm doomed to lust after it from afar, unless Dapper Cycles is able to bring them to market...and I somehow manage to afford one. Maybe by then the exotic bike-to-spare kidney exchange rate will improve.

    By the way, I wanted to say how much I've been enjoying Lovely Bike for the past 6 months or so that I've been aware of it. For my money, it's the single best bike blog out there. Indeed, it inspired me to start my own!

    -- Robert
    (Dandy Cycle: an appreciation of the proper gentleman's bicycle)

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  30. MDI - Although I use the "once you add stuff to the bike, the weight of the frame does not matter" argument myself, I think that it only applies to commuter and touring bikes. When it comes to roadbikes and racing bikes, the weight of the frame does matter - simply because it makes up a greater proportion of the bicycle's overall weight. Also, racing components tend to be lighter than touring and commuter components, exaggerating this difference even further. Even my vintage fixed gear roadbike benefits a great deal from the light weight of its Columbus frame, because it has so few components on it. If the frame was hi-ten, I'd feel the difference.

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  31. Robert - thank you : ) Clicked on your blog and I love that Raleigh advert with the girls in short-shorts going for the apples. I think one of them has the exact same saddle shoes as I do!

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