Complicated builds and having fun at Bohemian…

8 07 2011

I like a challenge, but recently I have gotten a lot of inquiries during frame school to build a particular type of bicycle which is about as difficult or challenging as it can get.

It comes down to a few types.  These consist a full touring and or Randonneur bicycle with integrated everything.   Ultra modern, straight fork, disks, big tubing and an integrated seat post aka. the SpeedVagen. Lastly, the monster/fat/cargo/electric/double boinger/beer cart/rolling couch or whatever other genre you can imagine.

So I am writing this entry so that I can refer students to it and they can learn the pluses and pitfalls of such designs.

First, we only have two weeks.  You must keep that in mind and one of those weeks is filled with discussions of frame geometry, metallurgy, design, and various practice sessions in filing, welding, fitting and alignment.    So, really what is left is one full unadulterated week to build.    Of course I don’t expect a Padawan learner to know how long it takes to make a bike frame but the short of it is, for a professional with experience it generally takes between 20 and 100 hours to complete a bicycle frame.   Twenty hours would be for a nice, clean road frame with lugs and 100 might be for a Randonneur frame with racks, lights etc (I have spent a lot longer than that BTW)   For someone doing it the first time count on it taking 2-3 times longer at least.   You can see that with only 90 hours of total instruction and work time during a course that it is near impossible to build some of these more difficult variants.

Probably my main concern with these complex builds is how does that translate into a quality learning scenario for the student?  Trust me, everyone freaks out at  just the thought of building a standard bicycle frame once you are into the throws of doing it.   To add large amounts of complexity only means two things.   Total overload and or I have to do major segments of the build which take away from bench time for you, the student.   I also want to point out that as a professional I did not start out building Peter Weigle’s Randonneur frames or Vanilla Speedvagens or ornate Bohemians.    We as builders have worked into this stage by building our skills, failing at times, learning constantly and maybe after a decade were able to attempt and succeed at accomplishing this.   To do this as a first try is beyond challenging to say the least and I worry may not lead to having FUN!  Really, its supposed to be fun and working with a deadline until you have blisters all over your hands is not fun.  It has happened, keep it in mind.

I also find that there is a new consumer of product that is discovering traditional steel bicycles after starting with the more ubiquitous carbon road frame of today.    They bring to this the aesthetic and design solutions that they are familiar with and hope to convert this to metal.   Examples are sloping top tubes,  massively oversized tubing, tapered steerers, straight forks, disk brakes, internal routes for brakes and derailleurs, integrated seat posts etc.

The breadth of designs is also greater than ever before.   Most students are stressed thoroughly enough just building a standard type of frame that has been in existence for 70 years.   Adding suspension, electric drives, monster tires etc all adds a massive increase in complexity.   I will say this.   If you want to build something like that the first order of business is to learn how to draft using CAD software.   Second is to learn how to join material.   There is not enough time by any stretch of the imagination to complete anything like these in a two week or even one month course.

One common error is translating designs that may be a necessity for carbon construction do not work well in steel.    Let’s look at an example.    Large oversize or tapered carbon steerers on forks.   Steel fork steers where traditionally 1’’ or 1.125’’ in diameter and showed though over 100 years to be strong and reliable.   Carbon fibers demanded that forks be designed differently because they are more reliable when made into large forms with smooth transitions.   This was not something that was ever needed for steel.   If we try and reverse engineer this what we end up with is a fork steerer that weighs a lot more just from the fact that it is bigger and also a steel head tube that doubles in weight because of it’s increased size.   Add in the increase weight of the bearings and such and now you have put half a kilo of mass where we never needed it only because we are trying to replicate a look rather than use proper engineering and the materials properties to ensure good design.

The same thing is evident for tubing, integrated seat posts, straight forks and internal cable routes which are very easy to do in carbon and difficult to do in metal.

One of my other concerns is will each technique teach the student all that they can be exposed to from the exercise?   A good example of this is straight bladed forks.   It is easier to build a straight bladed fork than a raked curved fork.   Straight bladed forks work well but initially were done to save labor and now with carbon it makes no sense to rake them.    With a steel fork though the rake can be varied which is not possible with straight designs and one learns the art of raking a fork correctly.   Build a straight fork and we forgo the knowledge of how to do a raked one.  Build a raked one and you can always build a straight one.

Certain designs just don’t work with steel very well.    An example of this is disk brakes for road or cyclocross use.   I look forward to the day we have great hydraulic brakes for road bikes but in the mean time there are maybe more disadvantages than advantages.   Mainly for steel road forks that is the added stresses that come from using a disk.   Steel road fork design currently dates back at least 60 years and they were not engineered with disks in mind.   To keep it simple what happens is that all the braking stress is on one side of the fork and in such a way that it works to un-rake the fork constantly.  In the worst scenarios this can cause the fork to twist permanently and essentially it is damaged beyond repair.    In order to alleviate this one would have to use fork blades that are much thicker and therefore heavier, stronger crowns and disk brake mounts.   Now onto the disk brake.  The only one that currently works well for road/cyclocross  is the Avid BB7 and although admirable it has its issues.   Disk rub and squeal for one.  Weighs a lot itself, add in the beefed up fork and downtube and it weighs more.   They interfere with rack placement and fender attachment as well.   The only thing I think one could really claim as being superior is alleviated rim wear but good ceramic coated braking surfaces will last at least 3 years under the hardest of use and honestly don’t cost a lot more than a new disk so I consider it standard wear items.   Maybe someday we will have much better options but heavy, noisy, and mounting difficulties make them not the best choice in my book for Randonneur or cyclocross bicycles.

Massively oversized tubing is another.   Steel is very stiff.  In fact the stiffest of all the metal frame materials.   If one emulates the diameters one finds in aluminum or carbon then it ends up being too stiff in steel.  One of the beauties of steel is being able to adjust the level of stiffness for the rider but too many riders today want to choose their tube diameters based on nothing other than aesthetics not proper engineering.   I have been blamed in my career of being too fancy.   Usually the line is something like this.  “What good does all that detail do?  It doesn’t make the bike any faster.   All I need is a simple tool that goes fast”   Conversely choosing tubing based on looks is no better than added frills and will make you slower not faster if overdone.

Some of you may be thinking that the course for you is not about learning so that you can replicate the process but just having a great time in Tucson and experiencing building a frame.  That I completely understand and respect,  if that is your intention then just relay that intention to me.   I will help.   There is still not enough time to build some of these complicated builds but I will as I have done before help you or finish the more complicated aspects of the build for you.   Of course there is a fee for this but if you would like polished dropouts, or internal cable routes or lug work that is beyond your abilities then all of this can happen it’s just that its not going to happen in the time allotted.   I will also offer a three week course if you like so that you have another 40+ hours of build time to finish these more complicated items and finish work.   If you would like that just inquire.

So to surmise,  I want you, the student to have a great time here.  I do not want you to be overwhelmed by complicated builds that are best left to persons with many years experience and I want you to end up with a great product you are going to be proud of, not one that was so challenging that the final result was less than you hoped for.   Less is more here and being conservative usually leads to improved results and more satisfaction in your build and time here.    Please, just keep that in mind.




2 responses

29 07 2011
David seo

Hello! Mr.

I have been interested in your frame building course and have questions about .
Is it possible for a foreigner to enroll your courses.(I am a korean).
In your blog, you can customze your course for someone who want to be a pro. (I really want to start my frame building business, It’s my dream.)

Thanks in advance.

29 07 2011
David seo

oops!, I missed the question.
Can you provide me with 3~5 courses together, and When is it ?
In your blog, You had closed your courses in 2011.

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