Dave Moulton former bicycle framebuilder

The Art of Bicycle Frame Building

      Traditional frame building, that is a steel frame hand brazed is an art, a craft; it is not engineering. The tubing is a high tensile steel alloy; the tubes are cut to a perfect miter so one tube fits exactly against the next and a steel lug is used to complete the joint. The joint is heated with an oxyacetylene hand held torch and brass is melted into the joint. The molten brass is drawn through the lug by capillary attraction and the end result is a very strong joint with one tube actually brazed to the next with the lug acting as reinforcement.

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Hand cut lugs, an expression of the frame builders art.

         The alloy steel tube has an inherent strength some of which is lost when heated; the trick is to work quickly and keep the flame constantly moving and to heat only the area as close to the lug as possible. Early lugs were nothing more than pipe fittings. As frame tubing became thinner to reduce weight the heavy square cut cast lugs would cause a stress point and the tube would often break at the joint. To overcome this the frame builder would file down the lugs and sculpt them into intricate shapes. This became the way a frame builder expressed his individuality.  
   
   
   
   
   
   
   
   
   
   
   
   
     

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        The engineer’s approach to frame building is to build a jig or fixture to hold the tubes in perfect alignment and then braze it together. The problem with this is that metal expands on heating and contracts as it cools down. Held in a jig the frame can go nowhere as it expands and as it cools will go where it wishes and spring out of alignment when removed from the jig.  
        My traditional approach was to assemble a frame in a jig for the sake of speed and accuracy, but braze it out of the jig held in a simple wooden block in a vise so the frame could expand and contract freely. With experience I got to know which way a frame would go and would actually build them out of alignment so they would end up in alignment on cooling. The amount a frame was set out of align was not a measured amount, it was a feeling. Much the same as an artist mixes paint to get a certain color, they do not measure the paint, it is a feeling.  
     
   

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        After brazing I would check my frames on a perfectly flat granite surface table and they would consistently be within 10 or 15 thousandth of an inch of true alignment. This is why I say frame building is an art not engineering. Engineering is working with precise measurements and calculations but art is a feeling or a knowing what is right. Part of the beauty of the racing bicycle is that it is a perfect marriage of the human body and machine. In designing a custom frame to fit an individual I used three basic measurements; overall height, inside leg and shoe size. From these measurements I could visualize the finished frame, tube lengths, angles and overall geometry.  
        There was no magic formula or calculation involved it was a knowing that came with years of experience. There are some who would not like to think I was using only "guesswork" to design frames. I would however add that it was an educated guess. Take a look at the photo below of a racing tandem I built.  
     
   

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  Paul Swinnerton (Front) and Trevor Gadd (Rear) represented Great Britain and rode this special 'Dave Moulton' track tandem in the 1978 World Championship.  
 

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        Here was not one but two very big men fitted to one frame. The one six feet tall, the other six-four. These two fit perfectly on this machine; there is no  wasted space. And look at the overall proportions of men and machine, there is balance and form. Which brings me to another theory I have: If something is designed correctly from a purely functional point of view, then it will look right from an aesthetic point of view. This is true of a boat, a building or a bridge, or any form of what I call functional art.  
        Progress often means the demise of the craftsman. Sailboats were once made of wood and it took a craftsman to shape and fit the wood together to form a watertight hull. Now sailboats are made from fiberglass and once a mold is made a semi-skilled worker can make a boat hull. Bicycle frame building is no different, new materials, tig welded aluminum and titanium frames and composite molded frames no longer require the degree of craftsmanship previously needed. This is progress; one cannot fight it or condemn it.  
 

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        As a craftsman, an artist I knew my creativity came from somewhere deep within me. It is not a right brain - left brain thing, it comes from ones very being. The heart as some artists say. I knew if I had been successful in one creative field I could do so in another.  
        This is the theme of my book Prodigal Child. The main character Eddie Conner learns as a child of a "Spirit of Creativity" within him. This carries him through the many misfortunes of his youth to later excel at any creative endeavor he partakes. Unfortunately I did not learn of my "Spirit of Creativity" until about the time I left the bicycle business, but it was always there. How else did I design frames that fit and build frames that were straight all by guesswork?  
     
   

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These tandem frames were a pain to build. I nick-named them "Tantrums." I am however particularly proud of this one.

Note the special rear handlebars clamped to the frame. One of my innovations.

These track tandems with a single fixed gear and no brakes reach speeds of 55 mph on a banked track.

 

  
   

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Schwinn British National Indoor Cycling Team.
(L to R) Mark Simmons, Steffano Ruggeri, Margaret Walton, Paul Swinnerton, Paul Venning,

 

 

 

 

Update September 26, 2004. I received an email from Paul Swinnerton. ( He’s the one pictured above on the front of the tandem.)

I came across your web site quite by chance. I am now into indoor cycling with Schwinn, being one of their British team demo riders. I still have my tandem hanging in my barn. The tandem was an incredible ride and each time I look at it, it brings some fantastic times and adrenalin rushes back to me.

After I finished racing in 1985 I trained in Karate and Jujitsu, and went on to fight for GB international competition. Not too far from sprinting really; I just hadn't finished competing. My tandem partner Trevor Gadd now lives in Canada. I also manage my Mum and Dad's bike shop. www.swinnertoncycles.co.uk

 

  

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