Steel is the oldest material used in bike frame construction. Indeed until the early nineties it was the only choice albeit in a multitude of guises. Reynolds, Columbus, and other smaller concerns offered tubing to suit every facet of the sport, from lowly training frames through to Tour de France climbing specials.
Over the years demand for ever lighter stiffer frames has dictated as shift to aluminum for mass produced frames and steel has become much more of a niche material.
But the tubing manufacturers have not allowed it to just die off. While aluminum, carbon and titanium have advantages over steel none are a perfect replacement.
There are several methods that a framebuilder can employ in constructing a frame from steel.
Most common is the classic lugged and brazed approach. The bike frame tubes are mitred to fit tightly onto cast or pressed lugs and brazed together to form a strong, reliably light frameset. With very light thin tubesets silver solder is employed to avoid overheating and weakening the frame.
A more elegant method is fillet brazing. This dispenses with the lugs and instead a smooth joint of brass is built up around the junction of each tube. This results in a frame where the tubes seem to flow into each other. It also enables the framebuilder to accommodate unusual frame designs not possible with lugs.
Both lugged and fillet brazed bike frames are easy to repair as damaged tubes can be heated at the joints, removed and a fresh tube substituted.
The most recent development is TIG welding. This is only possible on tubing designed to take the higher temperatures involved. It results in a very light stiff structure but unlike brazed and soldered construction it is harder to repair.
The choice of tubing available today, while not as large as in past years is still quite wide. Columbus, Reynolds and Dedacciai all offer several tubesets including the stainless steel 953 from Reynolds and XLR from Columbus.
A quality steel bike frame can be light and stiff yet absorb much of the road buzz that an alloy bike frame will not.
Source by Sean C Dowden