Original Posted By:> "Larry Williams"
Larry:Good steel bicycle frames are soldered with a silver/lead solder that has a melting point much lower than the brass used in brazing. This would avoid the crystallization problem.High end bicycle frames aren't made out of cromoly steel anymore, they are either titanium or carbon fiber - at least for the road bikes I'm familiar with, I don't know what the BMX people are doing.At least one local custom bike builder with a good reputationstill welds his cromoly custom frames. These are almost always touring bikes because the racers don't buy steel frames.You can buy kits to build your own bike, these offer pre-fab steel tubes that vary in diameter, thickness and cross sectionalong their length to accommodate the forces present in that specific location. This is much more sophisticated than whatwe are doing with our engine mounts, landing gear, etc.Also, the racing bicyclists are so fanatical about weight that they demand the frame set be as light as possible. This means that the tortional stress from pedaling causes stress fractures in the frame after just one or two seasons of use. These guysexpect their frame to break, we expect ours not to.Randy Stockberger