I am selling a Motobecane Super Mirage frameset with 2040 tubing. I would like to, at least, appear knowlegeable about the material when approached by prospective buyers. I have done exhaustive research on Google and can only find that it is "high tensile steel". Is there more that anyone has to offer as to the composition of this 2040 material, the frame construction, or even this frame as relates to Motobecane Super Mirages? If dating the frame is of use, there are pictures available at http://www.doug-morgan.com/BikeSales/Motobecane.html and it came with a Sun Tour V-GT Luxe rear derailer and Weinmann center-pull brakes. Your assistance in this matter will be greatly appreciated.