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I'm sure for many bike builders, their ultimate dream bike starts with a frame that they designed themselves. And herein lies the problem: it seems that modern means of frame production (e.g., hydroforming) implies very sophisticated shapes of frames, not just a bunch of round tubes welded together.

Is the design of a frame (together with rigidity calculations) something a layperson can reasonably pick up without taking a Mechanical Engineering degree? I'm curious about how all this stuff is actually learned and whether there are some places (training?) that explain it less than a few years.

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    Hydroforming is typically used on aluminum to help tune compliance or stiffness. It is also more the domain of mass production. These same ride properties can be achieved by custom frame builders through the careful selection of tubing dimensions and butting schedules when choosing steel tubing to use on the frame. Also other aspects such as how tubes are joined can further tweak ride characteristics. If anything hydroforming lets mass produced frames ride more like custom builds. – Rider_X Feb 11 '18 at 18:25
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    The Wright Brothers pretty much taught themselves to build bike frames from scratch (using wood, no less). – Daniel R Hicks Feb 11 '18 at 21:29
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    If you really want to learn, probably your best bet would be to apprentice yourself to another frame builder. – Daniel R Hicks Feb 11 '18 at 21:30
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    Obligatory Graeme Obree link, who beat the best aerodynamic carbon frames money could buy in the World Chmapionships using some spare Reynolds steel tubes he welded in the back of his friends bike shop. (en.wikipedia.org/wiki/Graeme_Obree) – Smeato Feb 12 '18 at 10:49
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Interesting question and way of looking at it.

Here's my take: those in the bike world who would seem most qualified to design scientifically optimal frames, which involves both mastery of all the advanced fabrication techniques and materials that are now available and the motivation to empirically figure out the handling and ride feel elements that can be hard to quantify, and which suffer when you just make things more stiff ad infinitum, usually end up working for companies where all the actual design decisions get made from a marketing and immediate profit perspective. The main question they spend their careers answering is, "How do we stay in the black in the next 2-3 years?" That's not to say that proper engineers aren't responsible for making some good bikes or moving the needle of progress and knowledge in the bike world forward, but they are not the only ones who do, and the mainstream companies they work for wind up pushing back the wrong direction on the needle quite often as well.

Small framebuilders usually aren't proper engineers, they usually don't have access to the same range of advanced materials and techniques, and they work in environments where myth, lore, and intuition can have louder voices than scientific process, but they're usually in a better position to deliver optimized ride feel and handling experiences to the end user. A lot of the major trends and advancements in the industry get started by non-engineers working at a grassroots level. And, to answer your question, you can get started in that world by riding, reading, geeking out, taking framebuilding classes (usually 1-2 weeks), and participating in existing forums.

Some other important pieces:

Round tubes start to have some meaningful disadvantages for high level athletes in high level competition. For everyone else all the rest of the time, bikes based on round and simple ovalized tubes aren't stiffness- or weight-impaired in any meaningful way.

If one does want to mess with more physically dialed frames, you don't have to be an engineer. You can just start doing carbon layups in your garage. Yes, without training you probably won't be able to do it with the same level of sophistication an engineer could. But you also won't be hamstrung by a marketing department or the need to make a product that has mass market appeal or that works for pros. So whether you actually wind up with a product that's any worse than theirs is not foretold by your lack of a degree.

  • Most people don’t have an autoclave in the garage. – Eric Shain Feb 12 '18 at 4:06
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    "usually end up working for companies where all the actual design decisions get made from a marketing and immediate profit perspective" - There are also frame designers working for national bike teams - where the question is "how can we shave a second off the time here (and hang the comfort)" – Martin Bonner Feb 12 '18 at 11:51
  • You don't need an autoclave as an amateur. You can follow boatbuilding practice using marine epoxy, (West Systems if you can afford it!) but with carbon weave instead of glass (as some boatbuilders do for spars). There will be a weight penalty compared to best practice, but if you can, vacuum bagging to squeeze out excess resin will reduce that somewhat. – Brian Drummond Feb 12 '18 at 14:56
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I remember seeing courses about how to make a bike frame, but they were not about new designs, they used standard designs and the courses were about selection of tube, welding/brazing, finishing, etc.

Perhaps you start by learning to braze, then building a "conventional" lugged steel frame, then develop that based on what you learn in the process.

This plan would assume a level of competancy with your hands, and a commitment in terms of tools and learning. Expect to take anything from months to years to be able to build a rideable reliable and safe frame.

Courses:

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