I started a new frame this week. Unlike all of my other frames which were designed for adults this particular frame was designed for a very special little nine year old girl. Typically I would never do a custom bike for a kid (ok, maybe for my own kids but that is just a Dad thing). Kids grow so fast that anything more than your typicall off the shelf bike is overkill. That is if any of the bikes that are currently available are small enough to fit your needs. The particular requirements for this frame was first a stand over height that was not over 14". "Specialized" 16" kids bike has a 16 1/4" stand over height making it not an option. Also they needed a frame that she did not have to hop on the seat just to get going. When the current bikes seat that they were using was dropped all the way to its lowest point it was still almost 18" off the ground. Meaning that someone with a 14" inseam had to hop 4" up to the saddle. The biggest challenge however was not the stand over and seat height it was that fact that due to the cost of any custom bike they wanted the bike to be able to "grow" with their daughter. While I know I did not want to do some kind of "expanding" bike what I thougth might be possible was to make the frame adaptable to either 16" or your typical 20" bmx wheel. This meant that as their daughter grew they could swap out the wheels for bigger wheels and maybe a taller handlebars, yet still have a bike that was designed for her proportions (if not specific size).
One of the ways I was able to get a shorter stand over height was by curving the top and down tubes. While I understand this is not exactly a new idea in the world of bikes (look at any woman's cruiser bike) it was new for me. After the pruchase of the Harbor Freight tube roller and some custom precision rollers I was able to get a pretty nice section of curved tubing. Being that I just used it on straight gauge tubeing I am really curious to see how it performs on the double butted stuff I normally use.