Bike Frame design

[reachdean]

I'm a "retired" bike mechanic with 8 years in a shop environment who now looks after the fleet at home (6 bikes) plus the bikes of a few good riding buddies in exchange for an occasional steak dinner. I've built everything there is to build on a bike, except for the frame. At present, I am wrapping up the restoration of a cedar strip canoe, and am looking for a new project. So designing and building my own frame is potentially the new goal.

I think I'm mostly narrowed down on the idea of a 650B hardtail mountain bike. Mostly because I don't already own one, and my quiver has most of the other bases covered. The other alternative would be a longtail, but I don't have space for such things in my apartment.

I am involved in motorsports and have friends who build some of the best cages in Canada, so I'm thinking of building in Cro-mo as I can have them teach me to weld, and they can oversee and make sure my welds are good. I'd love to build ti, but I figure I should screw up a frame or two before I go to such expensive materials. However, I am also intrigued by the idea of a Bamboo or wood frame. The path to either of those options is seemingly more complex than building in cro-mo.

So rather than riding a bunch of bikes to find a fit I like and then copying that, I'd prefer to find information and resources that will help me think about what I want to build and go from there. I'd be curious to hear where people think I should start, and why. I'm not typically one to shy away from big projects, provided they are interesting, and having something that is uniquely my own is appealing. I COULD go to some frame building school, but I learned how to braze in middle school, and want more choice than what can be had in lugged joints (at least I think I do).

Basically, the idea is to have fun, try things and see if I can do something unique.

So, open the floodgates and tell me what you know and how you know it. The second determines how much stock I put in the first.

 

[redneck44]

Does any one do frame building courses over there.
In the UK there are a some places that hold frame building courses which you end up with your own frame at the end of it.
Might be a way of getting what you want without having to make several trial runs first.

 

[reachdean]

Yes, there are frame building courses certainly in the USA, and probably here in Canada too.

That said, I don't really see a lot of appeal in a frame building school. All the ones I've seen cost as much or more than a custom ti frame, or enough tubing for 10 cro-mo frames. If I am going to spend that kind of money, I'd rather skip the mess and get a custom ti frame. I also don't see myself having the time to attend these schools. This is likely a project that will evolve over the course of time here, time there, rather than taking two weeks for a course, or trying to cram a course into two weekends.

 

[Christophe Noel]

I started my frame building apprenticeship in 1991 with Mark Nobilette and then went on to build quite a few frames for myself and other builders. I was also an instructor at Barnett's bike institute for a while. My advice...take the class. Of the bike building craft, welding and brazing are but a tiny portion of the process, as odd as that sounds. It's really about the art of geometry, frame dynamics through geometry and materials, and most importantly - fit dimensions. I've watched some of the most talented fabricators from outside the bike world make some stunningly welded junk bicycles.

There's an art to tube shaping for bicycles that most fabricators just don't understand, and why would they. I would go to a class. I would STRONGLY recommend going to a class. The UBI school of frame building is pretty solid. I'd start there. Just for discussion's sake, I spent a solid year working under Marc as a pair of extra hands before I built my first frame. But, once I joined my own frame, I was skilled enough to build frames for anyone. If you brave it alone, you can guarantee your first dozen frames will be real hoopty mobiles. Why take that road?

 

[reachdean]

With respect, I'm not looking to go out and just start buying and welding tubesets.

I appreciate welds are but one part of the whole process. I have contacts with a number of local framebuilders. Of the ones I have contacted, most are willing to impart SOME info. Plus, I am certain I can find more out there. I don't expect I'd be buying tubing for at least a couple of years while I research, learn, design, check, learn more, etc.

The reality is that vacation time is so rare I won't be burning it up to go to a two-week school, and I don't think I'll learn much in the shorter two weekend format. Bottom line is that I'd rather be out there on trips than in a shop class.

To put it into context, I'm just about finished the restoration of a cedar strip canoe. I bought it at a garage sale for $150 and thought "how hard could it be?" The short answer has proven to be "Very." The long answer has included the words "Very Worthwhile." I could have bought a kit with all the forms and followed a set of instructions, but I actually managed to find excellent information on the process, and with a little bit of thinking, figured out solutions to all of my problems. It's a couple varnish coats shy of seeing water, and I;'ve learned WAY more than had I bought a kit or taken a canoe building class (I say that having talked with people who've taken the class).

I'm not saying classes are no good, but for me part of the appeal is going a different route. Researching, learning, trying, and ultimately succeeding. The class might be a faster, cleaner way to the same end, but it's not part of my preferred philosophy, and not really part of my vacation planning giving my limited time.

 

[Christophe Noel]

Ya Dean, I think you may regret trying to dive into frame building cold. As said above, the tool investment alone is often the single deal breaker for many would-be builders. You can fabricate your own jig easy enough, although you usually get out of it what you put into it, so the building of the jig often comes at greater time and expense than the frame itself. You can kind of fudge on the tools needed for mitering the tube ends, but you'll spend untold hours with a file in hand.

You'll also have to improvise tube benders and most importantly alignment tools, plus a few necessary taps and dies depending on your finished product.

Not trying to over complicate the process, but when I started building my own frames in my own space, I do recall plunking down at least $3000 to put my first $300 frame together.

There's another option. In many cases you can approach an existing builder and ask to help construct your own frame. Now, because having some looky loo over their shoulder, they often want extra dough to offset the time needed to entertain the client during the build process. I used to charge an extra $300. It took that much time when the client would say "watcha doing now..." every ten minutes. The bonus is, you end up with a custom frame you know is perfect on the first try.

 

[DaveInDenver]

Having access to tools and expertise is great if you're looking to build something right now or maybe even start making a few of them. But I get the urge to learn about the process, so if it was me I would maybe start with the library and see where it goes from there. Yeah, alignment and coming up with a clever way to miter and jig tubes, the fun part might just be figuring out ways to adapt a drill press and build a DIY table.

 

[Christophe Noel]

By the way, I sold my frame building tools to a structural engineer who built pedestrian bridges all over the world. His first five frames are now wall art because they were so poorly aligned or didn't fit him worth a dam.

 

[DaveInDenver]

Well, the problem was he's an engineer. We generally know jack squat about actually doing stuff. My wife is a structural engineer going on 20 years of experience mainly on heavy and light rail bridges, highrise curtain walls and various historic preservation (foundations, structure reinforcement, etc.). She took a weekend welding class just so she could tie a bit of the theory and realization together. Throughout our training and practice we end up just knowing a bunch of stuff in abstraction.

 

[Christophe Noel]

Dave, I was somewhat speaking to his ability to understand structural concepts and mostly to his meticulous nature with regard to measurements, diameters, yada, yada. He was actually a very solid welder after a short bit of practice.

I spent a few hours with James at Black Sheep in his shop and it reminded me what makes a great builder. He has a minimum of tools, but each one is perfectly honed to meet his needs. He just has an artisan's hand and a 30 year history as a rider to know how to extract what he wants out of a pile of tubes. Fun to watch, for sure.

http://expeditionportal.com/american-overlander-black-sheep-bikes-hand-crafted-bicycles/

 

[DaveInDenver]

Exactly, frame building struck me as an art that largely ignores your ability to quantify it. Professionally I can tell you in great detail the why-for of PCB design and manufacturing but in 15 years that has done nothing to change my lack of brain-muscle coordination and so my soldering remains steadfastly mediocre. I'm even NASA-STD-8739 and IPC J-STD-001 trained but that doesn't change my ham fists and the ability to pass the qualification tests required to perform deliverable operations. It's just another thing in which I'm clearly born as a donkey and not a stallion. I have my strengths I'm sure and maybe someday I'll figure them out.

 

[Christophe Noel]

My welding skills were adequate as a builder. My ability to design a cool frame was fine. What I lacked was the patience to build. I just didn't enjoy the process as much as I did the end result. It's why jigsaw puzzles make me nuts, too.

 

[Overcoucher]

Maybe start with bikecad to help design the frame?
http://www.bikecad.ca/quickapplet

then maybe getting some feedback from builders at the frame building section of mtbr:
http://forums.mtbr.com/frame-building/

You can see some projects that members have done, there are a few great builders who will sometimes answer questions

Alternately there is the velocipede salon, which I have read a few times in the past, seems to be a decent resource as well.
http://www.velocipedesalon.com/forum/f10/